Uhh..Fuck?

[AChimp]

The only reason you're getting these letters is because you ended up downloading some small part of some file from one of the servers that the MPAA/RIAA sets up to share files. These servers act like any other torrent seed, but track all of the IPs that connect to it.

It has nothing to do with which BitTorrent client you're using (althought, theoretically, you could make a client that reports what files you download, but that wouldn't prove the actual contents of the file, only the filename). There's no such thing as an "official" BitTorrent client... BitTorrent is a protocol, not a specific program.

Use the thing that Chojin linked to, and this will stop you from connecting to the known spy servers.

If you start freaking out and delete all your stuff, that's what the MPAA/RIAA wants. They know they can't prosecute everyone, so they'll just trace your IP, tell your ISP to warn you with some legal cuntery and then forget about you. All of the students that got sued were dumb enough to be hosting 16,000 files off of the computer networks of public institutions where your IP can be traced down to the dormitory room you're in.