Copyscape is an online plagiarism detection service that checks whether similar text content appears elsewhere on the web.

[6] Copyscape was launched in 2004 by Indigo Stream Technologies, Ltd., co-founded in 2003 by Gideon Greenspan.

[9] 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.

[10] Copyscape uses a set of algorithms to identify copied content that has been modified from its original form.