Libel, Slander and Defamation
Libelous statements, whether against persons or products, are published statements that are false and damaging. Slander is the same as libel in most states, but in spoken rather than written form.
The terms "libel" and "slander" are often subsumed under the broader term "defamation." It is a tort (a wrongful act) to harm another's reputation by defaming them.
There are three tests which the defamatory statement must meet in order for a plaintiff to prevail in a suit against you and your publisher:
Untrue. In order to be defamatory, the statement must be untrue. If the statement is true or substantially true, then it is not defamatory, and the case is over.
Damaging. In order for the plaintiff to prevail, the statement must have caused real and substantial harm to the person or business. The plaintiff must present evidence of the substantial harm done.
Knowingly false. The plaintiff must also show that the defendant knew the statement was untrue, but published or broadcast the statement despite that knowledge.
You can say or publish just about whatever you wish in our open society--so long as it is true.
Public Official vs Public Figure
The same liberal rule applies to both categories: To prevail in a libel case against you, in addition to showing that your statement is untrue and caused significant harm, a public official or a public figure must also prove "malice" -- that you acted in reckless disregard to the facts known to you and with intent to harm.
Obviously, because of this stipulation, you enjoy considerable protection when it comes to public personages, since proving malice (intent to harm) places a heavy burden on the prosecution.
Who are these public people? The status of "public official" is relatively easy to determine from public records.
The courts have determined that there are two types of public figures:
A "general purpose public figure" is someone who enjoys social prominence. Entertainers are in this category.
A "limited purpose public figure" -- someone who has intentionally placed themselves into prominence, such as a vocal activist on a given issue.
The reasoning is that the press has a First Amendment duty to report on such newsworthy people, and therefore published statements warrant such protection.
Who is a private person? None of the above. Now you see why lawyers get the big bucks.