Most sites describe their censorship to some degree within the terms of service (TOS) that all users must agree to. For example, YouTube’s TOS lists several things a user will agree to avoid when uploading videos or making comments. These things regard content with copyrights and trademarks, but for other content, it asks you follow "common-sense rules that will help you steer clear of trouble." However, in some cases there are existing laws that govern the content some social media users may be sharing. Mark B. Baer, founder of the law corporation Mark B. Baer, Inc. and a frequent contributor to The Huffington Post says to an extent the sites dictate their own rules separate from the government. "Social media sites are not owned and operated by the government, and therefore, the owners of those sites may limit otherwise constitutionally protected speech,” said Baer. “Sites have been known to allow otherwise constitutionally prohibited material to remain online until ordered otherwise by a court of law. The nude photos of celebrities were removed only after the sites received copyright takedown notices."
Depending on the website is the limit the censorship can do