Remember that TV show on VH1 where they would overlay little bubbles with fun facts over old-school music videos? I envision a Web 2.0 version of that concept.
Here’s how this would work. You could download a plug-in for your music player that would detect the song that is being played. The app would download any relevant pop-ups for that song and display them in cute little bubbles, just like the TV show. As the bubbles appear you have the option to give them a quick ‘thumbs-up / thumbs-down’ vote, which would increase/decrease the likelyhood of those pop-ups being shown. Also, if you think of a clever fact or witty remark, you’d have an option to submit it to the site through the plug-in. You could add a social aspect to this by showing a little pic of the submitter with the bubble, which you could click on and check out other bubbles they’ve created.