I have to say, there's only a problem while illegally downloading stuff (tv shows, films, ...) of course. BitTorrent itself is perfectly legal, and I've seriously used it many times to download Linux ISOs and similar. Also technically, it is the uploading that bittorrent does that is illegal.
The other day I made the mistake of downloading one of the last How I Met Your Mother episodes via torrent (the first time in years). Two weeks later I had a nice invoice over several hundred Euros in my mailbox :-(, and I know a couple other people to whom happened the same. That's why I wouldn't touch Popcorn Time with a ten feet pole.
I don't have a scanner ready, but it was a pretty standard letter. If you search for "Abmahnung Waldorf Frommer" you should find some cover letters (in German). Waldorf Frommer is one law firm that is well known for sending those letters.
It was basically one page explaining that one violated copyright, giving the file name, the date, and the IP address; then a few pages detailing the appropriate laws, explaining how utterly bad piracy is, and telling you how much trouble you are in. Then there was an invoice for a one time "license" for the episode, and the legal fees which were more than the license. Following that, there was a kind of contract you had to sign, agreeing to accept the license, and in case of repeat violation, agree to pay a much higher fee. If I remember correctly, there even was a filled out wire-transfer form you just had to sign and bring to the bank in the end.
If you didn't accept their conditions, and refuse to sign, then they would go to court, which is extremely risky. You might get exonerated, or you might have to pay a lot more, so in the end I just payed the few hundred euros.
Given that the reason I pirated in the first place was that I'm a student and currently can't really afford to buy the media, its especially frustrating...
Yeah, the recommendation of many lawyers is not to pay or sign. Rather, you get a lawyer, and sign a "modified" cease-and-desist letter in which you 1) admit to no guilt and 2) don't agree to pay anything. By law, you have to react to their letter in some way. If you don't pay, there is a 50/50 chance that they'll let it be, or that they'll take it to court. I'm not really sure how your chances are in court.
Recently, someone argued that their router had a known vulnerability, and the rights holders couldn't prove that their WiFi was not hacked, and that they downloaded the files themselves, so they were acquitted. (http://www.heise.de/newsticker/meldung/Filesharing-Klage-weg...)
In my case, there were two factors that made me pay: First, they were in the right. As annoying as it might be, and whatever my positions on "intellectual property" are, it's hard to argue against that. Secondly, the cable connection belonged to a friend, and I didn't want to expose that person to a couple years of legal uncertainty.
If a cease-and-desist letter is unjustified, or in a grey area, I would definitely stand up against it, because I believe I'd have a good chance in court.
What would you have done (in by that, I mean "what do you advise normal people who aren't well-known, don't have a good knowledge of technology, and don't have a ton of money, to do")?
I would have definitely gone to court arguing that my IP address and me are not the same entity.
On top of that I would have used the (firm) German privacy laws to use the discovery process to figure out if they had obtained my (private!) name, address etc in a legal way.
To me this seems like a racket and I highly doubt that the case would have ever gone to court.
The other day I made the mistake of downloading one of the last How I Met Your Mother episodes via torrent (the first time in years). Two weeks later I had a nice invoice over several hundred Euros in my mailbox :-(, and I know a couple other people to whom happened the same. That's why I wouldn't touch Popcorn Time with a ten feet pole.