|Type of site||Plagiarism Search|
|Owner||Indigo Stream Technologies|
|Launched||July 10, 2004|
|Revenue||From premium services|
|Alexa rank||1,076 (December 2013[update])|
Copyscape is used by content owners to detect cases of "content theft", in which content is copied without permission from one site to another. It is also used by content publishers to detect cases of content fraud, in which old content is repackaged and sold as new original content.
Given the URL or text of the original content, Copyscape returns a list of web pages that contain similar text to all or parts of this content. It also shows the matching text highlighted on the found web page. Copyscape banners can be placed on a web page to warn potential plagiarists not to steal content.
Copyscape also provides two paid services: Copysentry monitors the web and sends notifications by email when new copies are found, and Copyscape Premium verifies the originality of content purchased by online content publishers.
Design and independent evaluation
In 2013, independent plagiarism software tests  conducted by Professor Debora Weber-Wulff et al. of the University of Applied Sciences in Berlin found Copyscape Premium to be the third best performing service (after Urkund and Turnitin).
Reported use in plagiarism cases
Copyscape's use has been reported in cases involving online plagiarism:
- On August 6, 2009, Copyscape was cited as the means used to detect plagiarism before the 9th U.S. Circuit Court of Appeals.
- On March 18, 2005, Copyscape was reported as the means used to search the Internet for unauthorized use of materials in the case of Brayton Purcell LLP vs. Recordon & Recordon, filed in the United States District Court for the Northern District of California (361 F.Supp.2d 1135). According to Brayton Purcell, Copyscape was used to search the Internet for unauthorized use of materials on October 7, 2004.
- On April 6, 2005, Arve Bersvendsen, a Norwegian Web developer, used Copyscape to find a copy of a CSS tutorial he wrote posted on a site owned by Apple Inc. Bersvendsen claimed that Apple had infringed his copyright, and the content in question was immediately removed.
- On October 17, 2005, Paul Litterick of the New Zealand Association of Rationalists and Humanists used Copyscape to analyze Bruce Logan's published newspaper work, setting off a plagiarism scandal. Litterick found that some of Logan's work was taken (in most cases with permission) from Anglo-American sources, including The Heritage Foundation, the Conservative Christian Fellowship, the Institute for American Values, Digby Anderson of the Social Affairs Unit and writers Maggie Gallagher and Melanie Phillips. Litterick published the results in the Fundy Post (Issues 18 and 19). Logan retired from the Maxim Institute one month later.
- On December 9, 2005, Richard Stiennon, a blogger at ZDNet, used Copyscape to find six Web sites that had stolen and re-published an ISP business plan he had written.
Copyscape was launched in 2004 by Indigo Stream Technologies, Ltd., co-founded in 2003 by Gideon Greenspan.
- "Copyscape.com Site Info". Alexa Internet. Retrieved 2013-12-01.
- Steal this post, Elinor Mills, USA Today (Washington DC), February 8, 2007
- Online plagiarism strikes blog world, Maura Welch, Boston Globe, May 8, 2006
- Scanning for Scammers Before You Buy In, Karen E. Klein, BusinessWeek (New York), March 3, 2008
- Copyright Tool Will Scan Web For Violations, Kevin J. Delaney, The Wall Street Journal (New York), December 18, 2006
- 9th Circuit Finds for PI Firm Over Theft of Firm's Web Site Content, Petra Pasternak, The Recorder, August 6, 2009
- Brayton Purcell Llp v. Recordon & Recordon, 361 F.Supp.2d 1135 (N.D. Cal., 2005)
- Apple accused of copyright wrongs, Paul Festa, CNET News, April 11, 2005
- Apple and copyright violations, Arve Bersvendsen, April 6, 2005
- Deborah Hill Cone (October 27, 2005). "A new maxim for Maxim — don't plagiarise". National Business Review. Retrieved September 26, 2011.
- Copyscape, Richard Stiennon, ZDNET blog, December 9, 2005
- Gideon Greenspan