When a dog bites a man, that is not news, because it happens so often. But if a man bites a dog, that is news. — attributed to New York Sun city editor John B. Bogart (1848- 1921)
Unfortunately, it's become an increasingly common occurrence: a public official, outraged over something posted about him/her anonymously on the Internet, asks a court to issue a subpoena to find out the identity of the poster(s). The Legal Threats Database contains a number of examples, and the "Legal Protections for Anonymous Speech" section of the Legal Guide lays out the legal analyses that courts have used to evaluate these subpoenas.
So it wasn't too surprising when Pittsburg County, Oklahoma District Attorney Jim Bob Miller issued a subpoena to Harold King, operator of the McAlester Watercooler forum site, seeking information, including (oddly) social security numbers, to identify about 35 pseudonymous posters on the site. But what made the case unusual was that D.A. Miller was one of the individuals who had filed a complaint for criminal defamation (details here) against King with the local police.