At f8 Facebook, which had previously been stand-offish around music leaving the development of applications to third parties, announced partnerships with services including Spotify, Vevo, Deezer, iHeartRadio, Mixcloud, Rhaposdy and SoundCloud.

Key to this was Facebook's updated Open Graph, which allows developers to build apps showing what Facebook users are doing with music, such as what songs they are listening to.

"Over the past few years, developers have started to demonstrate that when music is discovered through friends, people listen ...