What is Turntable.fm?
Turntable.fm was a music-sharing site where you chose what you listen to, as live DJs played songs for your approval or disapproval. The similar music-streaming site, Pandora, also offers songs based on your vote, but is run by the computer and not real people online. Turntable shut down in December 2013.
Site entry was via Facebook, and required that you already have a friend within the site to enter. Once in, you chose between multiple rooms that each contained a certain music genre. DJs took turns selecting songs for the audience in real time, which audience then rated their choices and determined if they got played or not. Since it is invite-only through an already involved friend, you were guaranteed to already "know" at least one person in the online community. 1
It has not been made completely public because of its questionable legality status. The site's music-sharing nature could easily be purely profitable for the music industry and so completely liable for support from them, but it also could attract legal action. 2