This is for JustMe, of Peanut-butter-and-Bacon Sandwiches. She asked about Blip in the comments box a few days back. It's a neat site.
Basically you become a DJ. You build your own playlist of songs, based on what they have in their library--which is extensive. You can just listen to you own playlist, or listen to the main feed, which is a mix of what everyone is playing. If you hear something you like in the main feed, you can add it to your list. If you want to, you can explore what other DJs are playing. If you decide you like what you hear from them, you can make them a "favorite," which adds their playlist to yours. I have 11 favorite DJs so far, so when I hit play I get the past few days' worth of what everyone has been playing. There's always the option just to listen to your own list as well.
It's fun. One Sunday this fall my sister and I had a musical conversation using Blip. She'd play something, I'd respond with something it reminded me of. Or something by the same artist. Or something that had nothing to do with anything. Then she'd respond to that, and so on. It was a fun way to while away a Sunday afternoon.