websites which blackmail users

There are websites that collect some compromising information (like nude pictures) not to provide their users with interesting content, but with a different purpose – to blackmail and compromise people. For example, there are many websites and blogs that, despite dirty publications, respect other people and copyright. They remove compromising materials at the request of the owners. But there are websites that are trying to compromise users, blackmail and demand money for removal of compromising pictures and videos. In such cases it is advisable to contact the professionals who remove photos, videos and other information from the Internet. If you know of sites that are known for their unethical actions and cases of blackmail and discredit, please write about those abuse in comments.