The Bloggers' FAQ on Online Defamation Law provides an overview of defamation (libel) law, including a discussion of the constitutional and statutory privileges that may protect you.
Generally, defamation is a false and unprivileged statement of fact that is harmful to someone's reputation, and published "with fault," meaning as a result of negligence or malice. State laws often define defamation in specific ways. Libel is a written defamation; slander is a spoken defamation.
The elements that must be proved to establish defamation are:
a publication to one other than the person defamed;
a false statement of fact;
that is understood as
a. being of and concerning the plaintiff; and
b. tending to harm the reputation of plaintiff.
If the plaintiff is a public figure, he or she must also prove actual malice.
Is truth a defense to defamation claims?
Yes. Truth is an absolute defense to a defamation claim.