This really kicked-off with the Davenport-Lyons scare; a company of solicitors was hired by the media industries to harass and threaten suspected file-sharers.
Tens of thousands of emails and paper letters (which are always taken more seriously than emails) were sent out to people threatening them with court action unless they paid hundreds of pounds in compensation - typically £500.
They are still active and a lot of people pay up because Davenport-Lyons is a real law-firm and they are prepared to take cases to court. In reality they don't have a leg to stand on in court but many people are afraid of going to court because Davenport Lyons threaten that they will be sued for thousands of pounds instead of just a few hundred.
Davenport Lyons get the money either because people are scared into paying or confess guilt, but it's pure scare-tactics. If you get a scare-mail from Davenport Lyons ADMIT NOTHING! The same applies to phone calls; they will try to trick you into providing information, don't even give them your name or whether you own a computer. Treat them with absolute contempt.
Partly true.
It's very difficult to get taken to court for it - but the threat is there.
Filesharing's had its day, now. People will slowly come around to the fact that the free software isn't worth the Trojan/virus/update/...trouble.
Doesn't matter if you're on their list or not, you're not going to court unless you continue and repeatedly ignore warnings. We're not a draconian society, you know?