This is a really interesting Music Website "Heat map" put together by the good folks over at Virtual Music. This represents overall usage of all of the major music websites where music is streamed or downloaded. The green color indicates growth where the red color indicates a decline.
The most interesting part of this visualization is the reality of where all of these services stand in comparison with Youtube and Pandora (see below). Be sure to go over to their site to see the actual usage numbers (hover your mouse over each section of the map for user numbers and other detail