The Hype Machine is a web site that gathers songs posted on MP3 blogs and presents them in an easy to consume manner. It's main value to me seems to be discovering cool MP3 blogs - of which there seem to be a limitless amount. Just like the new cool bands that the world (my world then) has been flooded with since I started to read MP3 blogs. Honestly, I don't have time to even listen to the one or two tracks of all the new artists I am trying to get to grips with...
Hype Machine is particularly cool if you use the flash player as a radio... If you are using Airport Express then I recommend a side order of Airfoil which lets you route audio from any application (in this case the Hype machine flash player in Safari with a bunch of search results in it - for example I searched for "cover" here) to your remote speakers.
UPDATE - totally getting into this Hype Machine thing... I am just leaving the player going in the background (playing through my stereo using Airfoil remember) and it's like listening to a fantastic indie radio station like Singapore doesn't have, but you can skip tracks, and when you hear one you like you can go to the blogpost that posted the track and read more about the band and download the track there as well. How cool is that???
Link