Copyscape provides a free plagiarism checker for finding copies of your web pages online, as well
as two more powerful professional solutions for preventing content theft and content fraud:
Copyscape Premium provides more powerful plagiarism detection
than the free service, plus a host of other features, including copy-paste originality checks, batch search, private index, case tracking and an API.
Copysentry provides comprehensive protection for your website by automatically scanning the web daily or weekly and emailing you when new copies of your content are found.
Copyscape also offers free plagiarism warning banners for your website to warn potential plagiarists against stealing your content, a free tool to compare two web pages or articles, and a comprehensive guide to dealing with plagiarism.