So here is an example of it working: Let's pretend that my friend and I are going on a bike ride and we both will be listening to Spotify on our phones through our earbuds. with the app I can select a song, or playlist to play, and his phone and my phone will play the same music at the same time. But here's the important part. Spotify already lets two people play the same playlists and songs, but what it doesn't let you do is have them play synced up well enough so we can both enjoy a shared experience of listening to music together second to second. That is really the core is this whole app. It's being able to share a perfectly synced up music experience with 2 or possibly more people separately, but together. I'm imaging that maybe one person would act as the "music host" and other people with the app could sync up to him through the app on their phones. And all this would be fine to be done as simply as possible with as few pages needed to obtain this functionality. Technically I'm imaging the app would use the Spotify API to start songs at the same moment for everyone who is synced up, and possibly monitor once or twice throughout the song to ensure that there is less than a second or two of variation in the playback position of each person listening to that song.