Editing Season 18

{{Seasons}}'''Season 18''' of ''[[Arthur (TV series)|Arthur]]'' premiered on [[PBS]] on September 29, 2014 with "[[The Friend Who Wasn't There]]/[[Surprise!]]".<ref name="episode2" /><ref>https://twitter.com/ArthurRead/status/484352029020549122</ref> It concluded on September 11, 2015 with "[[The Pageant Pickle]]/[[Some Assembly Required]]".<ref name="klru9" />

The season was first announced on June 21, 2013<ref>https://www.facebook.com/photo.php?fbid=466938520065124</ref> and was in production throughout 2013 and 2014.<ref>http://nycc13.mapyourshow.com/5_0/sessions/sessiondetails.cfm?ScheduledSessionID=18A9CDC4 ([https://web.archive.org/web/20131206141126/http://nycc13.mapyourshow.com/5_0/sessions/sessiondetails.cfm?ScheduledSessionID=18A9CDC4 archived page]; retrieved 6 December 2013</ref><ref>https://www.facebook.com/PBSArthur/posts/10153290115030203</ref> Storyboarding began around early December 2013.<ref>https://www.facebook.com/permalink.php?story_fbid=537883082970667&id=385632154862428&comment_id=3212268</ref> It is the third one produced by [[9 Story Media Group|9 Story Entertainment]].<ref name="9story">http://www.animationmagazine.net/tv/partners-re-up-with-9-story-for-arthur/ ([https://web.archive.org/web/20140527235447/http://www.animationmagazine.net/tv/partners-re-up-with-9-story-for-arthur/ archived page]; retrieved May 27, 2014)</ref> There were 10 episodes in it.<ref>http://www.ket.org/tvschedules/series.episode.list.php?id=ARUR</ref>

[[Lydia Fox|Lydia]] was going to appear in this season,<ref>http://elwoodcitycentral.createaforum.com/arthur-news/arthur-ny-comic-con-2013/msg1747/#msg1747 ([https://web.archive.org/web/20131227061832/http://elwoodcitycentral.createaforum.com/arthur-news/arthur-ny-comic-con-2013/msg1747/#msg1747 archived page]; retrieved December 27, 2013)</ref><ref>https://www.facebook.com/photo.php?v=541987352560240 (see description)</ref> but the episode "[[Little Miss Meanie|Littlev]]

☀This article is about the Internet encyclopedia. For Wikipedia's home page, see Wikipedia's Main Page. For Wikipedia's visitor introduction, see Wikipedia's About Page. For other uses, see Wikipedia (disambiguation).

"The Free Encyclopedia" redirects here. For other encyclopedias, see List of encyclopedias.
{| class="infobox vcard"
|+Wikipedia
| colspan="2" |<br>
The logo of Wikipedia, a globe featuring glyphsfrom several writing systems<sup>[notes 1]</sup>
|-
| colspan="2" |[show]

Screenshot
|-
!
Type of site
|Online encyclopedia
|-
!Available in
|299 languages
|-
!Owner
|Wikimedia Foundation
|-
!Created by
|Jimmy Wales, Larry Sanger<sup>[1]</sup>
|-
!Slogan(s)
|''The free encyclopedia that anyone can edit''
|-
!Website
|wikipedia.org
|-
!Alexa rank
|5 <small>(Global, January 2018)</small>
|-
!Commercial
|No
|-
!Registration
|Optional<sup>[notes 2]</sup>
|-
!Users
|>309,812 active users<sup>[notes 3]</sup>and >72,982,901 registered users
|-
!Launched
|January 15, 2001; 17 years ago
|-
!Current status
|Active
|-
!
Content license
|CC Attribution / Share-Alike 3.0<br>
<small>Most text is also dual-licensed underGFDL; media licensing varies</small>
|-
!Written in
|LAMP platform<sup>[2]</sup>
|-
!OCLC number
|52075003
|}
'''Wikipedia''' (/ˌwɪkɪˈpiːdiə/<small> ( listen)</small> ''WIK-i-PEE-dee-ə'' or /ˌwɪkiˈpiːdiə/<small> ( listen)</small> ''WIK-ee-PEE-dee-ə'') is a free online encyclopedia with the mission of allowing anyone to create or edit articles.<sup>[3][''not in citation given'']</sup> Wikipedia is the largest and most popular general reference work on the Internet,<sup>[4][5][6]</sup> and is ranked the fifth-most popular website.<sup>[7]</sup> Wikipedia is a project owned by the nonprofit Wikimedia Foundation.<sup>[8][9][10]</sup>

Wikipedia was launched on January 15, 2001, by Jimmy Wales and Larry Sanger.<sup>[11]</sup> Sanger coined its name,<sup>[12][13]</sup> a portmanteau of ''wiki''<sup>[notes 4]</sup> and encyclo''pedia''. There was only the English-language version initially, but similar versions in other languages quickly developed, which differ in content and in editing practices. With 5,565,572 articles,<sup>[notes 5]</sup> the English Wikipedia is the largest of the more than 290 Wikipedia encyclopedias. Overall, Wikipedia comprises more than 40 million articles in 299 different languages<sup>[15]</sup> and, as of February 2014, it had 18 billion page views and nearly 500 million unique visitors each month.<sup>[16]</sup>

As of March 2017, Wikipedia has about 40,000 high-quality articles, known as Featured Articles and Good Articles, that cover vital topics.<sup>[17][18]</sup> In 2005, ''Nature'' published a peer review comparing 42 science articles from ''Encyclopædia Britannica'' and Wikipedia, and found that Wikipedia's level of accuracy approached that of ''Encyclopædia Britannica''.<sup>[19]</sup>''Time'' magazine stated that the remarkably open-door policy of allowing anyone to edit had made Wikipedia the biggest and possibly the best encyclopedia in the world and it was testament to the vision of Jimmy Wales.<sup>[20]</sup>

Wikipedia has been criticized for allegedly exhibiting systemic bias, presenting a mixture of "truths, half truths, and some falsehoods",<sup>[21]</sup> and, in controversial topics, being subject to manipulation and spin.<sup>[22]</sup>

== Contents ==
 [hide] 
* 1History
** 1.1Nupedia
** 1.2Launch and early growth
** 1.3Milestones
* 2Openness
** 2.1Restrictions
** 2.2Review of changes
** 2.3Vandalism
* 3Policies and laws
** 3.1Content policies and guidelines
* 4Governance
** 4.1Administrators
** 4.2Dispute resolution
* 5Community
** 5.1Diversity
* 6Language editions
* 7Critical reception
** 7.1Accuracy of content
** 7.2Quality of writing
** 7.3Coverage of topics and systemic bias
** 7.4Explicit content
** 7.5Privacy
** 7.6Sexism
* 8Operation
** 8.1Wikimedia Foundation and Wikimedia movement affiliates
** 8.2Software operations and support
** 8.3Automated editing
** 8.4Wikiprojects, and assessments of articles' importance and quality
** 8.5Hardware operations and support
** 8.6Internal research and operational development
** 8.7Internal news publications
* 9Access to content
** 9.1Content licensing
** 9.2Methods of access
* 10Cultural impact
** 10.1Readership
** 10.2Cultural significance
** 10.3Sister projects – Wikimedia
** 10.4Publishing
** 10.5Scientific use
* 11Related projects
* 12See also
* 13References
** 13.1Notes
* 14Further reading
** 14.1Academic studies
** 14.2Books
** 14.3Book reviews and other articles
* 15External links

== History ==
Main article: History of Wikipedia

Jimmy Wales and Larry Sanger

=== Nupedia ===
Wikipedia originally developed from another encyclopedia project called Nupedia

Other collaborative online encyclopedias were attempted before Wikipedia, but none were as successful.<sup>[23]</sup>

Wikipedia began as a complementary project for Nupedia, a free online English-language encyclopedia project whose articles were written by experts and reviewed under a formal process.<sup>[11]</sup> Nupedia was founded on March 9, 2000, under the ownership of Bomis, a web portal company. Its main figures were Jimmy Wales, the <abbr>CEO</abbr> of Bomis, and Larry Sanger, editor-in-chief for Nupedia and later Wikipedia. Nupedia was licensed initially under its own Nupedia Open Content License, switching to the GNU Free Documentation License before Wikipedia's founding at the urging of Richard Stallman.<sup>[24]</sup> Sanger and Wales founded Wikipedia.<sup>[25][26]</sup> While Wales is credited with defining the goal of making a publicly editable encyclopedia,<sup>[27][28]</sup>Sanger is credited with the strategy of using a wiki to reach that goal.<sup>[29]</sup> On January 10, 2001, Sanger proposed on the Nupedia mailing list to create a wiki as a "feeder" project for Nupedia.<sup>[30]</sup>
{| class="infobox"
|+External audio
| colspan="2" |The Great Book of Knowledge, Part 1, Ideas with Paul Kennedy, CBC, January 15, 2014
|}

=== Launch and early growth ===
Wikipedia was launched on January 15, 2001, as a single English-language edition at www.wikipedia.com,<sup>[31]</sup> and announced by Sanger on the Nupedia mailing list.<sup>[27]</sup> Wikipedia's policy of "neutral point-of-view"<sup>[32]</sup> was codified in its first months. Otherwise, there were relatively few rules initially and Wikipedia operated independently of Nupedia.<sup>[27]</sup> Originally, Bomis intended to make Wikipedia a business for profit.<sup>[33]</sup>

Wikipedia gained early contributors from Nupedia, Slashdot postings, and web search engine indexing. By August 8, 2001, Wikipedia had over 8,000 articles.<sup>[34]</sup> On September 25, 2001, Wikipedia had over 13,000 articles.<sup>[35]</sup> By the end of 2001, it had grown to approximately 20,000 articles and 18 language editions. It had reached 26 language editions by late 2002, 46 by the end of 2003, and 161 by the final days of 2004.<sup>[36]</sup> Nupedia and Wikipedia coexisted until the former's servers were taken down permanently in 2003, and its text was incorporated into Wikipedia. The English Wikipedia passed the mark of two million articles on September 9, 2007, making it the largest encyclopedia ever assembled, surpassing even the 1408 ''Yongle Encyclopedia'', which had held the record for almost 600 years.<sup>[37]</sup>

Citing fears of commercial advertising and lack of control in Wikipedia, users of the Spanish Wikipedia forked from Wikipedia to create the ''Enciclopedia Libre'' in February 2002.<sup>[38]</sup> These moves encouraged Wales to announce that Wikipedia would not display advertisements, and to change Wikipedia's domain from ''wikipedia.com'' to ''wikipedia.org''.<sup>[39]</sup>

Though the English Wikipedia reached three million articles in August 2009, the growth of the edition, in terms of the numbers of articles and of contributors, appears to have peaked around early 2007.<sup>[40]</sup> Around 1,800 articles were added daily to the encyclopedia in 2006; by 2013 that average was roughly 800.<sup>[41]</sup> A team at the Palo Alto Research Center attributed this slowing of growth to the project's increasing exclusivity and resistance to change.<sup>[42]</sup> Others suggest that the growth is flattening naturally because articles that could be called "low-hanging fruit"—topics that clearly merit an article—have already been created and built up extensively.<sup>[43][44][45]</sup>

In November 2009, a researcher at the Rey Juan Carlos University in Madrid (Spain) found that the English Wikipedia had lost 49,000 editors during the first three months of 2009; in comparison, the project lost only 4,900 editors during the same period in 2008.<sup>[46][47]</sup> ''The Wall Street Journal'' cited the array of rules applied to editing and disputes related to such content among the reasons for this trend.<sup>[48]</sup> Wales disputed these claims in 2009, denying the decline and questioning the methodology of the study.<sup>[49]</sup> Two years later, in 2011, Wales acknowledged the presence of a slight decline, noting a decrease from "a little more than 36,000 writers" in June 2010 to 35,800 in June 2011. In the same interview, Wales also claimed the number of editors was "stable and sustainable".<sup>[50]</sup> A 2013 article titled "The Decline of Wikipedia" in MIT's ''Technology Review'' questioned this claim. The article revealed that since 2007, Wikipedia had lost a third of the volunteer editors who update and correct the online encyclopedia and those still there have focused increasingly on minutiae.<sup>[51]</sup> In July 2012, ''The Atlantic'' reported that the number of administrators is also in decline.<sup>[52]</sup> In the November 25, 2013, issue of ''New York'' magazine, Katherine Ward stated "Wikipedia, the sixth-most-used website, is facing an internal crisis".<sup>[53]</sup>

Wikipedia blackout protest against SOPA on January 18, 2012

A promotional video of the Wikimedia Foundation that encourages viewers to edit Wikipedia, mostly reviewing 2014 via Wikipedia content

=== Milestones ===
In January 2007, Wikipedia entered for the first time the top-ten list of the most popular websites in the U.S., according to comScore Networks. With 42.9 million unique visitors, Wikipedia was ranked number 9, surpassing ''The New York Times'' (#10) and Apple (#11). This marked a significant increase over January 2006, when the rank was number 33, with Wikipedia receiving around 18.3 million unique visitors.<sup>[54]</sup> As of March 2015, Wikipedia has rank 5<sup>[7][55]</sup> among websites in terms of popularity according to Alexa Internet. In 2014, it received 8 billion pageviews every month.<sup>[56]</sup> On February 9, 2014, ''The New York Times'' reported that Wikipedia has 18 billion page views and nearly 500 million unique visitors a month, "according to the ratings firm comScore."<sup>[16]</sup>

On January 18, 2012, the English Wikipedia participated in a series of coordinated protests against two proposed laws in the United States Congress—the Stop Online Piracy Act (SOPA) and the PROTECT IP Act (PIPA)—by blacking out its pages for 24 hours.<sup>[57]</sup> More than 162 million people viewed the blackout explanation page that temporarily replaced Wikipedia content.<sup>[58][59]</sup>

Loveland and Reagle argue that, in process, Wikipedia follows a long tradition of historical encyclopedias that accumulated improvements piecemeal through "stigmergic accumulation".<sup>[60][61]</sup>

On January 20, 2014, Subodh Varma reporting for ''The Economic Times'' indicated that not only had Wikipedia's growth flattened but that it has "lost nearly 10 per cent of its page-views last year. That's a decline of about 2 billion between December 2012 and December 2013. Its most popular versions are leading the slide: page-views of the English Wikipedia declined by 12 per cent, those of German version slid by 17 per cent and the Japanese version lost 9 per cent."<sup>[62]</sup> Varma added that, "While Wikipedia's managers think that this could be due to errors in counting, other experts feel that Google's Knowledge Graphs project launched last year may be gobbling up Wikipedia users."<sup>[62]</sup> When contacted on this matter, Clay Shirky, associate professor at New York University and fellow at Harvard's Berkman Center for Internet and Security indicated that he suspected much of the page view decline was due to Knowledge Graphs, stating, "If you can get your question answered from the search page, you don't need to click [any further]."<sup>[62]</sup>

By the end of December 2016, Wikipedia was ranked fifth in the most popular websites globally.<sup>[63]</sup>

== Openness ==
Number of English Wikipedia articles<sup>[64]</sup>

Wikipedia editors with >100 edits per month<sup>[64]</sup>

Differences between versions of an article are highlighted as shown

Unlike traditional encyclopedias, Wikipedia follows the procrastination principle<sup>[notes 6][65]</sup> regarding the security of its content.<sup>[65]</sup> It started almost entirely open—anyone could create articles, and any Wikipedia article could be edited by any reader, even those who did not have a Wikipedia account. Modifications to all articles would be published immediately. As a result, any article could contain inaccuracies such as errors, ideological biases, and nonsensical or irrelevant text.

=== Restrictions ===
Due to the increasing popularity of Wikipedia, popular editions, including the English version, have introduced editing restrictions in some cases. For instance, on the English Wikipedia and some other language editions, only registered users may create a new article.<sup>[66]</sup> On the English Wikipedia, among others, some particularly controversial, sensitive and/or vandalism-prone pages have been protected to some degree.<sup>[67][68]</sup> A frequently vandalized article can be ''semi-protected'' or ''extended confirmed protected'', meaning that only autoconfirmed or extended confirmed editors are able to modify it.<sup>[69]</sup> A particularly contentious article may be locked so that only administrators are able to make changes.<sup>[70]</sup>

In certain cases, all editors are allowed to submit modifications, but review is required for some editors, depending on certain conditions. For example, the German Wikipedia maintains "stable versions" of articles,<sup>[71]</sup> which have passed certain reviews. Following protracted trials and community discussion, the English Wikipedia introduced the "pending changes" system in December 2012.<sup>[72]</sup> Under this system, new and unregistered users' edits to certain controversial or vandalism-prone articles are reviewed by established users before they are published.<sup>[73]</sup>

The editing interface of Wikipedia

=== Review of changes ===
Although changes are not systematically reviewed, the software that powers Wikipedia provides certain tools allowing anyone to review changes made by others. The "History" page of each article links to each revision.<sup>[notes 7][74]</sup> On most articles, anyone can undo others' changes by clicking a link on the article's history page. Anyone can view the latest changes to articles, and anyone may maintain a "watchlist" of articles that interest them so they can be notified of any changes. "New pages patrol" is a process whereby newly created articles are checked for obvious problems.<sup>[75]</sup>

[[Little Miss Meanie| Miss Meanie]]" was made part of [[season 19]] instead.

==Episodes==

== ☀This article is about the Internet encyclopedia. For Wikipedia's home page, see Wikipedia's Main Page. For Wikipedia's visitor introduction, see Wikipedia's About Page. For other uses, see Wikipedia (disambiguation). ==
"The Free Encyclopedia" redirects here. For other encyclopedias, see List of encyclopedias.
{| class="infobox vcard"
|+Wikipedia
| colspan="2" |<br>
The logo of Wikipedia, a globe featuring glyphsfrom several writing systems<sup>[notes 1]</sup>
|-
| colspan="2" |[show]

Screenshot
|-
!
Type of site
|Online encyclopedia
|-
!Available in
|299 languages
|-
!Owner
|Wikimedia Foundation
|-
!Created by
|Jimmy Wales, Larry Sanger<sup>[1]</sup>
|-
!Slogan(s)
|''The free encyclopedia that anyone can edit''
|-
!Website
|wikipedia.org
|-
!Alexa rank
|5 <small>(Global, January 2018)</small>
|-
!Commercial
|No
|-
!Registration
|Optional<sup>[notes 2]</sup>
|-
!Users
|>309,812 active users<sup>[notes 3]</sup>and >72,982,901 registered users
|-
!Launched
|January 15, 2001; 17 years ago
|-
!Current status
|Active
|-
!
Content license
|CC Attribution / Share-Alike 3.0<br>
<small>Most text is also dual-licensed underGFDL; media licensing varies</small>
|-
!Written in
|LAMP platform<sup>[2]</sup>
|-
!OCLC number
|52075003
|}
'''Wikipedia''' (/ˌwɪkɪˈpiːdiə/<small> ( listen)</small> ''WIK-i-PEE-dee-ə'' or /ˌwɪkiˈpiːdiə/<small> ( listen)</small> ''WIK-ee-PEE-dee-ə'') is a free online encyclopedia with the mission of allowing anyone to create or edit articles.<sup>[3][''not in citation given'']</sup> Wikipedia is the largest and most popular general reference work on the Internet,<sup>[4][5][6]</sup> and is ranked the fifth-most popular website.<sup>[7]</sup> Wikipedia is a project owned by the nonprofit Wikimedia Foundation.<sup>[8][9][10]</sup>

Wikipedia was launched on January 15, 2001, by Jimmy Wales and Larry Sanger.<sup>[11]</sup> Sanger coined its name,<sup>[12][13]</sup> a portmanteau of ''wiki''<sup>[notes 4]</sup> and encyclo''pedia''. There was only the English-language version initially, but similar versions in other languages quickly developed, which differ in content and in editing practices. With 5,565,572 articles,<sup>[notes 5]</sup> the English Wikipedia is the largest of the more than 290 Wikipedia encyclopedias. Overall, Wikipedia comprises more than 40 million articles in 299 different languages<sup>[15]</sup> and, as of February 2014, it had 18 billion page views and nearly 500 million unique visitors each month.<sup>[16]</sup>

As of March 2017, Wikipedia has about 40,000 high-quality articles, known as Featured Articles and Good Articles, that cover vital topics.<sup>[17][18]</sup> In 2005, ''Nature'' published a peer review comparing 42 science articles from ''Encyclopædia Britannica'' and Wikipedia, and found that Wikipedia's level of accuracy approached that of ''Encyclopædia Britannica''.<sup>[19]</sup>''Time'' magazine stated that the remarkably open-door policy of allowing anyone to edit had made Wikipedia the biggest and possibly the best encyclopedia in the world and it was testament to the vision of Jimmy Wales.<sup>[20]</sup>

Wikipedia has been criticized for allegedly exhibiting systemic bias, presenting a mixture of "truths, half truths, and some falsehoods",<sup>[21]</sup> and, in controversial topics, being subject to manipulation and spin.<sup>[22]</sup>

== Contents ==
 [hide] 
* 1History
** 1.1Nupedia
** 1.2Launch and early growth
** 1.3Milestones
* 2Openness
** 2.1Restrictions
** 2.2Review of changes
** 2.3Vandalism
* 3Policies and laws
** 3.1Content policies and guidelines
* 4Governance
** 4.1Administrators
** 4.2Dispute resolution
* 5Community
** 5.1Diversity
* 6Language editions
* 7Critical reception
** 7.1Accuracy of content
** 7.2Quality of writing
** 7.3Coverage of topics and systemic bias
** 7.4Explicit content
** 7.5Privacy
** 7.6Sexism
* 8Operation
** 8.1Wikimedia Foundation and Wikimedia movement affiliates
** 8.2Software operations and support
** 8.3Automated editing
** 8.4Wikiprojects, and assessments of articles' importance and quality
** 8.5Hardware operations and support
** 8.6Internal research and operational development
** 8.7Internal news publications
* 9Access to content
** 9.1Content licensing
** 9.2Methods of access
* 10Cultural impact
** 10.1Readership
** 10.2Cultural significance
** 10.3Sister projects – Wikimedia
** 10.4Publishing
** 10.5Scientific use
* 11Related projects
* 12See also
* 13References
** 13.1Notes
* 14Further reading
** 14.1Academic studies
** 14.2Books
** 14.3Book reviews and other articles
* 15External links

== History ==
Main article: History of Wikipedia

Jimmy Wales and Larry Sanger

=== Nupedia ===
Wikipedia originally developed from another encyclopedia project called Nupedia

Other collaborative online encyclopedias were attempted before Wikipedia, but none were as successful.<sup>[23]</sup>

Wikipedia began as a complementary project for Nupedia, a free online English-language encyclopedia project whose articles were written by experts and reviewed under a formal process.<sup>[11]</sup> Nupedia was founded on March 9, 2000, under the ownership of Bomis, a web portal company. Its main figures were Jimmy Wales, the <abbr>CEO</abbr> of Bomis, and Larry Sanger, editor-in-chief for Nupedia and later Wikipedia. Nupedia was licensed initially under its own Nupedia Open Content License, switching to the GNU Free Documentation License before Wikipedia's founding at the urging of Richard Stallman.<sup>[24]</sup> Sanger and Wales founded Wikipedia.<sup>[25][26]</sup> While Wales is credited with defining the goal of making a publicly editable encyclopedia,<sup>[27][28]</sup>Sanger is credited with the strategy of using a wiki to reach that goal.<sup>[29]</sup> On January 10, 2001, Sanger proposed on the Nupedia mailing list to create a wiki as a "feeder" project for Nupedia.<sup>[30]</sup>
{| class="infobox"
|+External audio
| colspan="2" |The Great Book of Knowledge, Part 1, Ideas with Paul Kennedy, CBC, January 15, 2014
|}

=== Launch and early growth ===
Wikipedia was launched on January 15, 2001, as a single English-language edition at www.wikipedia.com,<sup>[31]</sup> and announced by Sanger on the Nupedia mailing list.<sup>[27]</sup> Wikipedia's policy of "neutral point-of-view"<sup>[32]</sup> was codified in its first months. Otherwise, there were relatively few rules initially and Wikipedia operated independently of Nupedia.<sup>[27]</sup> Originally, Bomis intended to make Wikipedia a business for profit.<sup>[33]</sup>

Wikipedia gained early contributors from Nupedia, Slashdot postings, and web search engine indexing. By August 8, 2001, Wikipedia had over 8,000 articles.<sup>[34]</sup> On September 25, 2001, Wikipedia had over 13,000 articles.<sup>[35]</sup> By the end of 2001, it had grown to approximately 20,000 articles and 18 language editions. It had reached 26 language editions by late 2002, 46 by the end of 2003, and 161 by the final days of 2004.<sup>[36]</sup> Nupedia and Wikipedia coexisted until the former's servers were taken down permanently in 2003, and its text was incorporated into Wikipedia. The English Wikipedia passed the mark of two million articles on September 9, 2007, making it the largest encyclopedia ever assembled, surpassing even the 1408 ''Yongle Encyclopedia'', which had held the record for almost 600 years.<sup>[37]</sup>

Citing fears of commercial advertising and lack of control in Wikipedia, users of the Spanish Wikipedia forked from Wikipedia to create the ''Enciclopedia Libre'' in February 2002.<sup>[38]</sup> These moves encouraged Wales to announce that Wikipedia would not display advertisements, and to change Wikipedia's domain from ''wikipedia.com'' to ''wikipedia.org''.<sup>[39]</sup>

Though the English Wikipedia reached three million articles in August 2009, the growth of the edition, in terms of the numbers of articles and of contributors, appears to have peaked around early 2007.<sup>[40]</sup> Around 1,800 articles were added daily to the encyclopedia in 2006; by 2013 that average was roughly 800.<sup>[41]</sup> A team at the Palo Alto Research Center attributed this slowing of growth to the project's increasing exclusivity and resistance to change.<sup>[42]</sup> Others suggest that the growth is flattening naturally because articles that could be called "low-hanging fruit"—topics that clearly merit an article—have already been created and built up extensively.<sup>[43][44][45]</sup>

In November 2009, a researcher at the Rey Juan Carlos University in Madrid (Spain) found that the English Wikipedia had lost 49,000 editors during the first three months of 2009; in comparison, the project lost only 4,900 editors during the same period in 2008.<sup>[46][47]</sup> ''The Wall Street Journal'' cited the array of rules applied to editing and disputes related to such content among the reasons for this trend.<sup>[48]</sup> Wales disputed these claims in 2009, denying the decline and questioning the methodology of the study.<sup>[49]</sup> Two years later, in 2011, Wales acknowledged the presence of a slight decline, noting a decrease from "a little more than 36,000 writers" in June 2010 to 35,800 in June 2011. In the same interview, Wales also claimed the number of editors was "stable and sustainable".<sup>[50]</sup> A 2013 article titled "The Decline of Wikipedia" in MIT's ''Technology Review'' questioned this claim. The article revealed that since 2007, Wikipedia had lost a third of the volunteer editors who update and correct the online encyclopedia and those still there have focused increasingly on minutiae.<sup>[51]</sup> In July 2012, ''The Atlantic'' reported that the number of administrators is also in decline.<sup>[52]</sup> In the November 25, 2013, issue of ''New York'' magazine, Katherine Ward stated "Wikipedia, the sixth-most-used website, is facing an internal crisis".<sup>[53]</sup>

Wikipedia blackout protest against SOPA on January 18, 2012

A promotional video of the Wikimedia Foundation that encourages viewers to edit Wikipedia, mostly reviewing 2014 via Wikipedia content

=== Milestones ===
In January 2007, Wikipedia entered for the first time the top-ten list of the most popular websites in the U.S., according to comScore Networks. With 42.9 million unique visitors, Wikipedia was ranked number 9, surpassing ''The New York Times'' (#10) and Apple (#11). This marked a significant increase over January 2006, when the rank was number 33, with Wikipedia receiving around 18.3 million unique visitors.<sup>[54]</sup> As of March 2015, Wikipedia has rank 5<sup>[7][55]</sup> among websites in terms of popularity according to Alexa Internet. In 2014, it received 8 billion pageviews every month.<sup>[56]</sup> On February 9, 2014, ''The New York Times'' reported that Wikipedia has 18 billion page views and nearly 500 million unique visitors a month, "according to the ratings firm comScore."<sup>[16]</sup>

On January 18, 2012, the English Wikipedia participated in a series of coordinated protests against two proposed laws in the United States Congress—the Stop Online Piracy Act (SOPA) and the PROTECT IP Act (PIPA)—by blacking out its pages for 24 hours.<sup>[57]</sup> More than 162 million people viewed the blackout explanation page that temporarily replaced Wikipedia content.<sup>[58][59]</sup>

Loveland and Reagle argue that, in process, Wikipedia follows a long tradition of historical encyclopedias that accumulated improvements piecemeal through "stigmergic accumulation".<sup>[60][61]</sup>

On January 20, 2014, Subodh Varma reporting for ''The Economic Times'' indicated that not only had Wikipedia's growth flattened but that it has "lost nearly 10 per cent of its page-views last year. That's a decline of about 2 billion between December 2012 and December 2013. Its most popular versions are leading the slide: page-views of the English Wikipedia declined by 12 per cent, those of German version slid by 17 per cent and the Japanese version lost 9 per cent."<sup>[62]</sup> Varma added that, "While Wikipedia's managers think that this could be due to errors in counting, other experts feel that Google's Knowledge Graphs project launched last year may be gobbling up Wikipedia users."<sup>[62]</sup> When contacted on this matter, Clay Shirky, associate professor at New York University and fellow at Harvard's Berkman Center for Internet and Security indicated that he suspected much of the page view decline was due to Knowledge Graphs, stating, "If you can get your question answered from the search page, you don't need to click [any further]."<sup>[62]</sup>

By the end of December 2016, Wikipedia was ranked fifth in the most popular websites globally.<sup>[63]</sup>

== Openness ==
Number of English Wikipedia articles<sup>[64]</sup>

Wikipedia editors with >100 edits per month<sup>[64]</sup>

Differences between versions of an article are highlighted as shown

Unlike traditional encyclopedias, Wikipedia follows the procrastination principle<sup>[notes 6][65]</sup> regarding the security of its content.<sup>[65]</sup> It started almost entirely open—anyone could create articles, and any Wikipedia article could be edited by any reader, even those who did not have a Wikipedia account. Modifications to all articles would be published immediately. As a result, any article could contain inaccuracies such as errors, ideological biases, and nonsensical or irrelevant text.

=== Restrictions ===
Due to the increasing popularity of Wikipedia, popular editions, including the English version, have introduced editing restrictions in some cases. For instance, on the English Wikipedia and some other language editions, only registered users may create a new article.<sup>[66]</sup> On the English Wikipedia, among others, some particularly controversial, sensitive and/or vandalism-prone pages have been protected to some degree.<sup>[67][68]</sup> A frequently vandalized article can be ''semi-protected'' or ''extended confirmed protected'', meaning that only autoconfirmed or extended confirmed editors are able to modify it.<sup>[69]</sup> A particularly contentious article may be locked so that only administrators are able to make changes.<sup>[70]</sup>

In certain cases, all editors are allowed to submit modifications, but review is required for some editors, depending on certain conditions. For example, the German Wikipedia maintains "stable versions" of articles,<sup>[71]</sup> which have passed certain reviews. Following protracted trials and community discussion, the English Wikipedia introduced the "pending changes" system in December 2012.<sup>[72]</sup> Under this system, new and unregistered users' edits to certain controversial or vandalism-prone articles are reviewed by established users before they are published.<sup>[73]</sup>

The editing interface of Wikipedia

=== Review of changes ===
Although changes are not systematically reviewed, the software that powers Wikipedia provides certain tools allowing anyone to review changes made by others. The "History" page of each article links to each revision.<sup>[notes 7][74]</sup> On most articles, anyone can undo others' changes by clicking a link on the article's history page. Anyone can view the latest changes to articles, and anyone may maintain a "watchlist" of articles that interest them so they can be notified of any changes. "New pages patrol" is a process whereby newly created articles are checked for obvious problems.<sup>[75]</sup>


{| border="1" cellpadding="0" cellspacing="0" style="border-collapse: collapse" width="100%" id="AutoNumber1" bordercolor="#111111"
| width="140" align="center" bgcolor="#c808ff" | '''Screenshot'''
| width="43%" align="center" bgcolor="#c808ff" | '''Title'''
| width="12%" align="center" bgcolor="#c808ff" | '''Number'''
| width="13%" align="center" bgcolor="#c808ff" | '''Episode'''
| width="20%" align="center" bgcolor="#c808ff" | '''Original Airdate'''
|-
| width="140" rowspan="2" height="100" | [[File:The Tattletale Frog.png|140px]]
| width="42%" align="center" height="19" |"'''[[The Tattletale Frog]]'''"
| width="13%" align="center" height="19" | 206
| width="13%" align="center" height="19" | 1a<ref name=":0" />
| width="20%" align="center" height="19" |October 1, 2014<ref name=":0">[https://web.archive.org/web/20140907042104/http://www.klru.org/schedule/episode/259221/ The Tattletale Frog / D.w. & Bud's Higher Purpose | Arthur | KLRU TV Schedule | KLRU TV, Austin PBS] archived from the [http://www.klru.org/schedule/episode/259221/ original]</ref>
|-
| width="88%" colspan="4" height="81" |When [[Bud Compson|Bud]] is blamed for an accident [[D.W. Read|D.W.]] causes, she has to decide whether to let her friend take the fall.<ref name=":0" />
|-
| width="" rowspan="2" height="100" | [[File:D.W. & Bud's Higher Purpose.JPG|140px]]
| width="42%" align="center" height="19" |"'''[[D.W. & Bud's Higher Purpose]]'''"
| width="13%" align="center" height="19" | 206
| width="13%" align="center" height="19" | 1b<ref name=":0" />
| width="20%" align="center" height="19" |October 1, 2014<ref name=":0" />
|-
| width="88%" colspan="4" height="81" |D.W. and Bud can't wait to ride "[[The Buzzard]]", [[Wonderworld]]'s newest roller coaster. Will they make it past the persnickety [[Peter|ticket taker]]...or come up short?<ref name=":0" />
|-
| width="" rowspan="2" height="100" | [[File:The Friend Who Wasn't There.JPG|140px]]
| width="42%" align="center" height="19" |"'''[[The Friend Who Wasn't There]]'''"
| width="13%" align="center" height="19" | 207
| width="13%" align="center" height="19" | 2a<ref name="episode2" />
| width="20%" align="center" height="19" | September 29, 2014<ref name="episode2">http://www.ket.org/tvschedules/episode.php?nola=ARUR++001802</ref>
|-
| width="88%" colspan="4" height="81" |[[Muffy Crosswire|Muffy]] embarks on an epic quest to find [[Waldo|her long lost imaginary friend]]. But she has to be careful-the Crosswire basement is full of bewitched boxes and gadgets and dolls...oh my!<ref name="klru2">http://www.klru.org/schedule/episode/259222/</ref>
|-
| width="" rowspan="2" height="100" | [[File:Surprise.JPG|140px]]
| width="42%" align="center" height="19" |"'''[[Surprise!]]'''"
| width="13%" align="center" height="19" | 207
| width="13%" align="center" height="19" | 2b<ref name="episode2" />
| width="20%" align="center" height="19" | September 29, 2014<ref name="episode2" />
|-
| width="88%" colspan="4" height="81" | It's [[Catherine Frensky|Catherine]]'s 16th birthday, and [[Francine Frensky|Francine]] has been cordially uninvited to the party. With the help of her friends, she whips up the perfect present for her big sister...a sneaky surprise with a side of payback!<ref name="klru2"/>
|-
| rowspan="2" width="" height="100" | [[File:TCOTGWTLF_1.jpg|140px]]
| width="42%" align="center" height="19" |"'''[[The Case of the Girl with the Long Face]]'''"
| width="13%" align="center" height="19" | 208
| width="13%" align="center" height="19" | 3a<ref name="episode3" />
| width="20%" align="center" height="19" | September 30, 2014<ref name="episode3">http://www.ket.org/tvschedules/episode.php?nola=ARUR++001803</ref>
|-
| colspan="4" width="88%" height="81" |[[Fern Walters|Fern]] has been feeling low and no one can figure out why. Luckily, [[Buster Baxter|Buster]] is on the case! He'll leave no stone unturned, no lead unexplored, no ice cream uneaten...<ref name="klru3">http://www.klru.org/schedule/episode/259223/</ref>
|-
| rowspan="2" width="" height="100" | [[File:The Substitute Arthur.JPG|140px]]
| width="42%" align="center" height="19" |"'''[[The Substitute Arthur]]'''"
| width="13%" align="center" height="19" | 208
| width="13%" align="center" height="19" | 3b<ref name="episode3" />
| width="20%" align="center" height="19" | September 30, 2014<ref name="episode3" />
|-
| colspan="4" width="88%" height="81" |With [[Arthur Read|Arthur]] out of town, Buster is on the hunt for a new best friend. The problem is, he only wants to play games ''his'' way. Will he learn to compromise or is he destined to play alone?<ref name="klru3" />
|-
| rowspan="2" width="" height="100" | [[File:1804ami.jpg|140px]]
| width="42%" align="center" height="19" |"'''[[Best Wishes]]'''"
| width="13%" align="center" height="19" | 209
| width="13%" align="center" height="19" | 4a
| width="20%" align="center" height="19" |October 2, 2014<ref name=":1">http://www.klru.org/schedule/episode/259224/</ref>
|-
| colspan="4" width="88%" height="81" |After [[George Lundgren|George]] has a lucky streak, his friends pressure him to wish for a snow day. Can he deliver or is he out of luck?<ref name=":1" />
|-
| rowspan="2" width="" height="100" | [[File:1804bmi.jpg|140px]]
| width="42%" align="center" height="19" |"'''[[The Tardy Tumbler]]'''"
| width="13%" align="center" height="19" | 209
| width="13%" align="center" height="19" | 4b
| width="20%" align="center" height="19" |October 2, 2014<ref name=":1" />
|-
| colspan="4" width="88%" height="81" |[[Prunella Deegan|Prunella]] is excited about making the gymnastics team...until she realizes practice starts at 6am! Will she honor her commitment...or hit the snooze button?<ref name=":1" />
|-
| rowspan="2" width="" height="100" | [[File:Season 18 Promo.JPG|centre|thumb|140x140px]]
| width="42%" align="center" height="19" |"'''[[Fountain Abbey]]'''"
| width="13%" align="center" height="19" | 210
| width="13%" align="center" height="19" | 5a
| width="20%" align="center" height="19" | January 26, 2015<ref name="ket1805">http://www.ket.org/tvschedules/episode.php?nola=ARUR++001805</ref>
|-
| colspan="4" width="88%" height="81" |[[Muffy Crosswire|Muffy]] is devastated when she learns her great, great grandmother, [[Mary Alice Miller]], wasn't royalty, but a common maid. The indignity! However, her old diary reveals a more interesting story.<ref name="klru5">http://www.klru.org/schedule/episode/259225/</ref>
|-
| rowspan="2" width="" height="100" | [[File:ACI7.jpg|centre|thumb|140x140px]]
| width="42%" align="center" height="19" |"'''[[Arthur Calls It]]'''"
| width="13%" align="center" height="19" | 210
| width="13%" align="center" height="19" | 5b
| width="20%" align="center" height="19" | January 26, 2015<ref name="ket1805" />
|-
| colspan="4" width="88%" height="81" |Pressure from his classmates has Arthur doubting his decision to call Buster out during a baseball game. Will he succumb to peer pressure, or stick with what he believes is right?<ref name="klru5" />
|-
| rowspan="2" width="" height="100" | [[File:Whip-mix-blend.png|140px]]
| width="42%" align="center" height="19" |"'''[[Whip. Mix. Blend.]]'''"
| width="13%" align="center" height="19" | 211
| width="13%" align="center" height="19" | 6a
| width="20%" align="center" height="19" |September 7, 2015<ref name="klru6" />
|-
| colspan="4" width="88%" height="81" |When [[Rattles' mother]] starts dating [[Archie Vanderloo]], [[Rattles]] finds himself spending lots of time with Archie's twins. The problem is, he doesn't have anything in common with them! Can this blended family learn to get along?<ref name="klru6">http://www.klru.org/schedule/episode/259226/</ref>
|-
| rowspan="2" width="" height="100" | [[File:Staycation main image.png|140px]]
| width="42%" align="center" height="19" |"'''[[Staycation]]'''"
| width="13%" align="center" height="19" | 211
| width="13%" align="center" height="19" | 6b
| width="20%" align="center" height="19" |September 7, 2015<ref name="klru6" />
|-
| colspan="4" width="88%" height="81" |Arthur offers to babysit so that his parents can enjoy some peace and quiet in the backyard. What could go wrong? With D.W. on the loose...just about everything!<ref name="klru6" />
|-
| rowspan="2" width="" height="100" | [[File:1807atwominutes.png|140px]]
| width="42%" align="center" height="19" |"'''[[Two Minutes]]'''"
| width="13%" align="center" height="19" | 212
| width="13%" align="center" height="19" | 7a
| width="20%" align="center" height="19" |June 1, 2015<ref name=":2">http://idahoptv.org/schedules/listingDetails.cfm?TZ=MT&SeriesID=5066&thisChannel=KAID&VersionID=280543&ThisDate=6-1-2015&thisTime=07:30:00&ShowPast=1#Past</ref>
|-
| colspan="4" width="88%" height="81" |Power shifts in the [[The Tibbles' House|Tibbles' house]] when the [[Tibble Twins|twins]] find out Tommy is two minutes older than Timmy. Frustrated in his new role, Timmy enlists the help of an expert older brother tamer: D.W.!<ref name="klru7">http://www.klru.org/schedule/episode/259227/</ref>
|-
| rowspan="2" width="" height="100" | [[File:Messy Dress Mess main image.png|140px]]
| width="42%" align="center" height="19" |"'''[[Messy Dress Mess]]'''"
| width="13%" align="center" height="19" | 212
| width="13%" align="center" height="19" | 7b
| width="20%" align="center" height="19" |June 1, 2015<ref name=":2" />
|-
| colspan="4" width="88%" height="81" |[[Ladonna Compson|Ladonna]] is thrilled when Muffy loans her a beautiful recital dress. But a run-in with a painted bench leaves Ladonna wondering how to break the news to her fashionista friend.<ref name="klru7" />
|-
| rowspan="2" width="" height="100" | [[File:Arthur Read Super Saver main image.png|140px]]
| width="42%" align="center" height="19" |"'''[[Arthur Read: Super Saver]]'''"
| width="13%" align="center" height="19" | 213
| width="13%" align="center" height="19" | 8a
| width="20%" align="center" height="19" |September 10, 2015<ref name="klru8" />
|-
| colspan="4" width="88%" height="81" |Business is slow for [[David Read|David]] and [[Jane Read]], and Arthur is concerned. Can this "super saver" find ways to keep his family in the green?<ref name="klru8">http://www.klru.org/schedule/episode/259228/</ref>
|-
| rowspan="2" width="" height="100" | [[File:1808btibblestotherescue.png|140px]]
| width="42%" align="center" height="19" |"'''[[Tibbles to the Rescue]]'''"
| width="13%" align="center" height="19" | 213
| width="13%" align="center" height="19" | 8b
| width="20%" align="center" height="19" |September 10, 2015<ref name="klru8" />
|-
| colspan="4" width="88%" height="81" |When D.W. saves the Tibble twins from a nasty fall, they decide to repay the favor...whether she likes it or not.<ref name="klru8" />
|-
| rowspan="2" width="" height="100" | [[File:TPP7.jpg|140px]]
| width="42%" align="center" height="19" |"'''[[The Pageant Pickle]]'''"
| width="13%" align="center" height="19" | 214
| width="13%" align="center" height="19" | 9a
| width="20%" align="center" height="19" |September 11, 2015<ref name="klru9" />
|-
| colspan="4" width="88%" height="81" |School is almost out and Arthur can hardly wait for those lazy summer days by Muffy's pool. Nothing could ruin such a happy time of year...except maybe D.W.'s spring pageant!<ref name="klru9">http://www.klru.org/schedule/episode/259229/</ref>
|-
| rowspan="2" width="" height="100" | [[File:Some Assembly Required main image.png|140px]]
| width="42%" align="center" height="19" |"'''[[Some Assembly Required]]'''"
| width="13%" align="center" height="19" | 214
| width="13%" align="center" height="19" | 9b
| width="20%" align="center" height="19" |September 11, 2015<ref name="klru9" />
|-
| colspan="4" width="88%" height="81" |D.W. can't wait to test out her new playset! But while it's being built she'll have to settle for the box. With the help of Bud and [[Emily]], she realizes her imagination is way better than any toy!<ref name="klru9" />
|-
| rowspan="2" width="" height="100" | [[File:The shelter 1.png|140px]]
| width="42%" align="center" height="19" |"'''[[Shelter from the Storm]]'''"
| width="13%" align="center" height="19" | 215
| width="13%" align="center" height="19" | 10
| width="20%" align="center" height="19" |September 8, 2015<ref name="klru10" />
|-
| colspan="4" width="88%" height="81" |When a [[Hurricane Sadie|powerful hurricane]] hits [[Elwood City]], everyone's affected. [[Rufus Compson|Ladonna's dad]] is called up by the [[Army Corps of Engineers]]. Muffy relocates to a shelter, while Arthur struggles to reunite lost pets and owners. And [[Alan Powers|Alan]] seeks the help of a [[Dr. Paula|therapist]], voiced by special guest [[Idina Menzel]], to help him manage his anxiety.<ref name="klru10">http://www.klru.org/schedule/episode/259230/</ref>
|}

==Trivia==
*This is the first season to feature [[William Healy]] as the voice of Arthur, taking over from [[Drew Adkins]]. This is also the first season to feature [[Max Friedman Cole]] as the voice of Brain. Although he shared his role with [[Siam Yu]], who has been voicing Brain since [[Season 16]], due to his voice maturing in this season.
*This is the first season that [[Andrew Dayton]] does the voice of D.W.
*This is also the first season where [[Christian Distefano]] voices James. Distefano would later become the new voice actor of D.W. for Seasons [[Season 20|20]]-[[Season 21|21]], succeeding Andrew Dayton.

==Gallery==
<gallery widths=180>
Season 18 Buster detective promo.png|Promotional picture from Facebook.<ref>https://www.facebook.com/PBSArthur/photos/10154524172860203/</ref>
1801 DW promo.jpg|"What’s D.W. up to?  Find out on ARTHUR next Wednesday, 10/1 on PBS KIDS (check local listings)"<ref>https://www.facebook.com/PBSArthur/photos/a.501573345202.387485.43562115202/10154624663210203</ref>
Season 18 Promo.JPG
</gallery>

==External links==
*[http://www.wmht.org/blogs/kids/arthur-season-18/ WMHT blog post]
==References==
{{Reflist}}
[[Category:A to Z]]