They're a copyright troll that was suing John Does for pirating pornography. They'd go to court, say "this IP downloaded X" and subpeona for the identity of the

They're a copyright troll that was suing John Does for pirating pornography. They'd go to court, say "this IP downloaded X" and subpeona for the identity of the person assigned that IP. They'd then use the threat of the suit to attempt to extort a settlement out of the person identified in order to avoid the cost and embarrassment of being named in a suit for downloading porn. The judge in this case had already called them out on this and refused to allow discovery unless they could show that they could specifically identify the person that had committed the infringement (specifically noting that IPs identify the person paying for the IP, not necessarily the person who committed the act), and that they could minimize the likelihood of the incorrect person being named -- and therefore unfairly embarrassed -- by the suit. Prenda subsequently withdrew the case, but it turned out they were pulling all kinds of shady shell games that the judge is now looking into as willful misconduct and abuse of the court.