This is an interesting mash up. Spotisquare brings together Foursquare and Spotify and it enables you to attach a song to a location/check in, thus enabling you to put some personality to your Foursquare check ins. They have a mobile app at m.spotisquare.com . Obviously, a big issue is that Spotify is not readily available in the USA. And do we really need another task to do when checking in using Foursquare?