this can really be a killer app if done right. this increases the average time spent on fb further. currently fb and twitter are not doing anything about the users past activities like, likes/tweets/status updates etc., except for images in Facebook. if i wanted to look up an interesting thing i tweeted or shared in the past it is really not that intuitive and most of the time i give up. this music thing can be really huge similar to the images app, not just the live listing feature, currently there is no way to have all my liked music from various apps to be in one place.they may introduce a music tab, they also have my favourite artists, so they may fill my music tab with their songs if available. if done right this can be really huge, the most used app next to images. i hope they can deliver.