The list itself is pretty uninteresting if you've been keeping up at all with popular blogs, but there are two things that make it something worth checking out: First, the artwork for each artist is simply awesome. Some very intricate stuff (from various artists), and 90% of the time it represents the musician very well I think. Second, thanks to Grooveshark, you can stream every top 50 album for free straight from the list. And unsurprisingly if you know what the hype machine is, you can download each top 50 track fo free. Have at it:

Top 50 Artists
Top 50 Albums
Top 50 Tracks