I am not sure if anyone has already mentioned this but i really think there ought to be a search function of some description availiable on this site. I downloaded some mix tapes from sendspace to listen to but then found myself unable to remember who the original mixtaper was. It's not a huge deal but i feel i must contribute.

I'm going to venture a guess and say that's planned for 2.0. But I've run into the same dilemma. A way around it is to look up a track that's on the mix, and then click on the link that points you to what mixes that track has been used on.