My ex-wife has gone on Facebook and posted all sorts of comments and links that make me look like I like kiddie porn. Can I sue her and Facebook for this?
Assuming that what you're saying is true in terms of what your wife is doing -- and assuming also that what she is saying about you is not true -- then you can most likely sue your ex-wife for libel, which is a form of defamation that occurs when the defamatory statements are made in writing (and online publication qualifies as "in writing.")
Though definitions vary slightly from state to state, defamation is the publication of a false factual statement that brings harm to a person's reputation.
Here, being accused of participating in child pornography is obviously damaging, and if the statement was made online and was offered as a fact (not as an opinion), it will be actionable as libel, assuming it is not true.
In this case, it may come down to whether or not the statements or insinuations your ex made can be construed as opinion, or if they were intended as fact. Opinions are typically protected and are not actionable under defamation laws. But anything that is construed as a fact can be actionable as long as it's not true (truth is a defense to a defamation claim).
You should start by preserving evidence of the statement. Take screenshots or print out the screens where the statement was posted, and gather evidence that links your ex-wife to the screen name that was used to publish the statement. (Learn more in our article Defamation: The Basics.)
So, you've got a pretty good case against your ex-wife (again, assuming your version of the story is the true version), but you cannot sue Facebook. A federal law called the Communications Decency Act of 1996 is generally interpreted as protecting "interactive computer service" providers (like Facebook) from liability for statements posted by site users.
by: David Goguen, J.D.