We've been testing this new thing Rdio for a couple weeks now (coming very soon to the public) and frankly, we're kind of shocked no one has thought of it before: it's a streaming music site that has a pretty wide swathe of great music (personal test: yes, they are working on getting Kode9's DJ Kicks and yes, they have Busy Signal's latest LPs). You can stream songs infinitely, share stuff with your homies in a Twitter/tumblr format, and send your picks to your mobile to listen with no drama. Honestly, we're not usually impressed by this kind of stuff but we're genuinely psyched on Rdio. So we made a big playlist to correspond to all the music in our Summer Music issue, including tracks from all four cover stars (and one Madonna song! Read our Style Section!), and we're giving away a very limited amount of pre-open-to-the-public invites if you wanna go listen to it/BE OUR FRIEND ON YET ANOTHER SOCIAL MEDIA PLATFORM. Holler at the Twits and the Facebook! To sign up, head over to our page on Rdio.