To my surprise, this is a fairly well-established legal term in Georgia, with 18 references -- the earliest in 1962 and the most recent earlier this month.
The term is the Georgia courts' attempt to avoid the conceptual difficulty of deciding whether radio and television broadcasts should be labeled "libel" or "slander." Outside broadcasting, libel has traditionally referred to defamation by writing, pictures, or symbolic displays, and "slander" to defamation by speaking or some other sounds. Historically, the plaintiff had a harder time prevailing in civil slander cases than in civil libel cases; in an era where criminal libel prosecutions were common, libel was criminally punishable but slander generally was not; and more generally, slander, being evanescent, was generally seen as less harmful than libel. Defamation in broadcasting tended to consist of spoken words (though of course defamation on television could involve a writing), so it sounded like slander; but it had a large audience, so it sounded like libel. Different states pigeonholed broadcasting defamation in one or the other category, but Georgia decided to solve the problem by coining a new term.
So use it wisely, which is to say not at all outside Georgia. But don't be surprised if you hear it.