The idea behind starTunes was to be able to star rate my albums and artists, as currently you can only star rate tracks in iTunes. This way I could see which artists and albums I owned I had star rated the highest and were most likely to be the ones that I wanted to play.
The album star rating is just the average of all the star ratings of each track in each album, and the artist star rating is the average of the calculated star rating of each album by that artist. The genre star rating is just the average star rating of each artist in that genre.
