What.cd is a private Bittorrent tracker that probably has music on it, but nobody knows since none have ever managed to get an invite. (V& November 2016 - rest in shit)
Policy on Invites
"You are completely responsible for the people you invite. If your invitees are caught cheating or trading/selling invites, not only will they be banned, so will you. Be careful who you invite. Invites are a precious commodity."
There is an interview process for people who fail to get invited (that's you!) that actually isn't that hard. Going to this website will give a potential user all of the information he/she needs to get into the site, which includes a basic knowledge of lossy and lossless formats, transcodes, and what exactly is acceptable on the site.
What.cd has a huge library of music on it, because everyone is so desperate to get upload credit that they resort to uploading the most obscure Bandcamp releases and rare records they can find just to keep their pathetic ratios going. All of the music (with a few exceptions) is in a standard format, either FLAC or MP3 in most cases.
What.cd also has an active forums and community, and they talk about music a bunch, but they're insufferably autistic and the discussion is awful.