impersonation

[user1478771160]

Can someone advise me?

Someone or more than one person is posting in forums either by using my name or have included details that relate specifically to me. Some of the postings are either controversial or almost offensive to others.
This hasn't happened on this site I don't think but on at least three sites. Pete

Have you contacted the websites concerned? You should ask them to remove the offending posts.

You may be able to sue the impersonator for misuse of private information. If they have communicated with others who have shared personal information believing they are talking to you, those individuals would also have claims.

Posting offensive or controversial statements in your name may be defamatory.

If they have used your photographs that is a breach of copyright.

They may also be impersonating you with intent to commit fraud, which would make it a criminal matter.

there is sometimes an issue on facebook where I see friends of mine saying if I receive something (usually porno) purportedly from them then to ignore it.

I would let your friends know its been happening to you.