Bop.fm launched out of beta this week promising the end of song link and playlist frustration. By offering playlists that source songs from multiple services, including YouTube, SoundCloud, Rdio and Spotify, Bop.fm lets you use the sources to which you have access. This service makes it easier to enjoy songs and playlists across licensing and geographic boundaries. Bop.fm also has a player for web publishers that's currently in use on Rap Genius. So you may have already enjoyed their work.