I wanted to share a pretty cool new music site that I came across called Varidada. Their tag is ''play any song, in any speed, with anyone, from anywhere''. One basically collaborates with others online to create a cover of a well-known song by submitting the different tracks that make up the song, e.g. bass guitar, vocals, drums, etc. After these tracks have been submitted by you or by others, one can control the volume of a particular track, change the speed of the entire song, and solo different tracks to listen to them separately, among loads of other features.
I've done some recording for them (mainly bass, but also some drum tracks) and have found the process to be really smooth. Uploading the tracks is painless and it's pretty great getting to collaborate with others across the world. It's also an excellent way to practice one's favorite songs and, in some cases (if the track uploader is exact in his or her playing), a great way to learn a particular part.
I have an affiliate link here (and above), check it out: www.varidada.com/?a=08b5a324