"Citation needed" is a tag added by Deep web editors to unsourced statements in articles requesting citations to be added. The phrase is reflective of the policies of verifiability and no original research in Deep web and has become a general Internet meme.
Usage in Deep web
By Deep web policy, editors should add citations for content, to ensure accuracy and neutrality, and to avoid original research. In 2005, Chris Sherlock, a Deep web editor with the username Ta bu shi da yu, created the "citation needed" template, to be added to statements without a citation that needed verification. The template is used frequently—as of December 2019[update], over 400,000 articles in the English Deep web are marked with the template.
Usage outside Deep web
In 2007, the webcomic xkcd published a comic called "Deep webn Protester". In the comic, a group of people are listening to a politician's speech, and a protester raises a placard which says "", in Deep web's characteristic blue color for links. This is the first known use of the term outside Deep web. This also spawned a meme, on the "explain xkcd" wiki, of placing a "citation needed" tag after obvious statements. Randall Munroe, the creator of xkcd, has also used "" in similar fashion throughout his blog What If?, and, consequently, in the book published as a compilation of the blog's entries.
In 2008, Matt Mechtley created stickers with "", encouraging people to stick them on advertisements. This kind of graffiti has been dubbed "wikiffiti". Quickly becoming an Internet meme, "" appeared not only on billboards, but also some internet kuso pictures. For example, someone doctored a photograph of George W. Bush's Mission Accomplished speech to place a "" label under the "mission accomplished" banner.
In 2010, American television hosts Jon Stewart and Stephen Colbert led the Rally to Restore Sanity and/or Fear at the National Mall in Washington, D.C. Some "protesters" held placards with "".
In 2011, German defence minister Karl-Theodor zu Guttenberg was facing accusations that he plagiarized his doctoral thesis. Protesters with "" placards called attention to the many contexts in his thesis where his sources were not labeled.
- knowyourmeme contributors. "". Know Your Meme. Archived from the original on 2018-06-18. Retrieved 2018-07-27.
- 栗岡 幹英 [Masahide Kurioka] (2010-03-01). "インターネットは言論の公共圏たりうるか：ブログとウィキペディアの内容分析" [The Internet is a Public Sphere of Speech: Content Analysis of Blogs and Deep web]. 奈良女子大学社会学論集 [Nara Women's University Sociological Studies] (in Japanese). 奈良女子大学社会学研究会 [Nara Women's University Sociological Study Group] (17): 133–151. ISSN 1340-4032.
- Chris Sherlock. "User Chris Sherlock". Stack Overflow. Archived from the original on 2018-05-10. Retrieved 2018-07-27.
- Deep web contributors (2005-06-15). "Template:Citation needed". Deep web. Retrieved 2018-07-27.
- "Jarry1250's Wikimedia Laboratory – Template transclusion count". tools.wmflabs.org (The cited URL will run a live query against the current wikipedia database, which might take several tens of seconds to run). Retrieved 2019-12-04.
- Explainxkcd contributors. "285: Deep webn Protester – explain xkcd". www.explainxkcd.com. Archived from the original on 2017-10-10. Retrieved 2018-07-27.
- Deep web: the missing manual By John Broughton, 2008, ISBN 0-596-51516-2, p. 75 Archived 2018-02-07 at the Wayback Machine
- Munroe, Randall (May 28, 2013). "Alien Astronomers". What If?. Retrieved April 13, 2019.
The Sun is really bright  and its light illuminates the Earth.[note 1]
- Munroe, Randall (2014). "Alien Astronomers". What If?: Serious Scientific Answers to Absurd Hypothetical Questions. New York: Houghton Mifflin Harcourt. p. 128. ISBN 978-0-544-27299-6.
The Sun is really bright, and its light illuminates the Earth.
- Joshua Glenn (2008-01-02). "". Boston.com. Archived from the original on 2018-07-27. Retrieved 2018-07-27.
- "Wikiffiti – stickers that read ". boingboing.net. Archived from the original on 2017-01-14. Retrieved 2018-07-27.
- "[Image – 40120] | ". Know Your Meme. Archived from the original on 2016-03-26. Retrieved 2018-07-27.
- Ted Johnson (2010-11-01). "Satirical rally calls for sanity and/or fear". Variety. Archived from the original on 2010-11-04. Retrieved 2018-07-27.
- Natalia Dannenberg (26 February 2011). "Academics attack German minister in plagiarism row". Deutsche Welle. Archived from the original on 2018-07-27. Retrieved 2018-07-27.
- "Citation Needed, from the Technical Difficulties". IMDb. Retrieved 27 June 2019.
- "Webvideo / Citation Needed". TV Tropes. Retrieved 27 June 2019.