Ever wonder how the RIAA decides who to sue when it comes to its tens of thousands of music-sharing lawsuits? The Chronicle of Higher Education has discussed the matter in depth with an RIAA employee, who remains anonymous in this story, to outline exactly how it hunts down the people it eventually sues.

Those of us who live down the rabbit hole of tech know most of these details already, but if you're a casual technology user and have ever used a peer-to-peer app, you'll probably find this fascinating. That said, it's also interesting to hear directly from the RIAA confirming what we, for the most part, already knew.

Here's the digested version of the process: The RIAA uses MediaSentry, an independent company, to search LimeWire for a list of songs the RIAA's members own. MediaSentry just goes down the list, and when it finds a match, the IP address of the file sharer is recorded. There's no word on whether newer songs get more attention, but that seems probable.

MediaSentry matches the IP address to the ISP that owns it, and then the subpoenas kick in: Once the RIAA is given an IP address and the name of the ISP, it can subpoena that ISP for the identity of the subscriber that was using the IP address at that particular time. Then the lawsuits and DMCA notices fly, especially with regard to universities, where the bulk of infringement is said to take place and where results (that is, music being taken offline) are often swift.

Some important points: The RIAA doesn't, and can't, track who's downloading music, only who's sharing it on their hard drive. Though reports have surfaced in recent months that the RIAA might be running its own "honey pot" servers designed to trap people looking for illegal music, and that it seeds P2P networks with fake versions of popular songs, these activities don't appear to be the focus of the group. Nor should they, really: It is considerably easier to just search P2P networks for contraband rather than running your own in the hopes that a pirate will wander by.

Another interesting point: LimeWire is the only P2P network mentioned by name in the story. While other services, including eDonkey and BitTorrent, offer just as much (or more) copyrighted material, it's interesting to see that LimeWire may be a focus. MediaSentry may indeed search these other networks for contraband, but it's curious that LimeWire seems to be the focus.