The first version, which Webjay founder Lucas Gonze wrote about back in July, only allowed people to play mp3 files that were part of Yahoo’s music subscription service (which Silicon Alley Insider says may be on the block), and only on the Yahoo Music site. The latest version works for any content, anywhere. As Mike Arrington points out, lots of people have browser plugins that do the same thing — but lots of people don’t.
Yahoo’s solution is kind of cool, and an interesting first step towards what Rogers seems to have in mind for the future: a distributed web of content tied together by Yahoo tools. In a note to a music industry discussion list I’m on, Lucas pointed out some other features: sites can specify the cover art and other details of the player, including the order of songs played, and the documention for the player is a wiki.
There’s also a Flash version of the player that works on the same principle, and can be used to play embedded lists of files on the fly. You can point it at playlists, RSS feeds or websites and it will play whatever is in them. It was developed by a Yahoo developer (and transplanted Canadian) named William White, and there’s an embed code generator tool here. Yahoo also uses the Flash player in its Music Blogs app for Facebook.