It uses blocklists for the blocking, but IP ranges can also be configured manually. Pre-cofigured for blocking are RIAA, MPAA and many others.
All the RIAA needs to do is get some Comcast bandwidth.


I thought that RIAA has more sofisticated tools to browse p2p networks....
I'm sure they've had some third party build them clients to make things a little easier, perhaps to automate the process a bit... but they're still following protocol and the official clients will do the job without being fancy.