Copyscape is an online plagiarism detection tool that helps users identify duplicate content on the internet. It allows writers, publishers, and website owners to check if their work has been copied or if they are using content that is not original. By entering a URL or text, users can quickly see if similar content exists elsewhere. The service is particularly useful for maintaining content integrity and ensuring originality in SEO practices. By using Copyscape, individuals and businesses can protect their intellectual property and improve their online presence by avoiding penalties from search engines for duplicate content.