At least in some countries (mine included) you can't in fact buy music or video from iTunes. They won't accept your paypal or credit card.
There is a workaround -- buying and redeeming gift codes. But honestly, I can't be arsed to that.
I made something to show it off a year or so ago: http://richardlyon.co.uk/coffee/lastfm.php?artist=mogwai (switch from 3d to 2d if it's being a pain, change artist in URL to something you like)
UPDATE: @richthegeek, Thanks much appreciated.
A more update version of the graphing program (without the lastfm stuff) is visible at http://richthegeek.github.com/coffeegraph
Being a musician and considering moving to Bandcamp since the small labels I worked aren't very good at marketing their releases, I wonder how Bandcamp works for other artists compared to other stores like iTunes, amazon, etc. Are there any stats available?
Only downside is discovery of music on bandcamp, a side project I'm currently working on is a tool for myself to find new music on bandcamp; unfortunately their APIs aren't designed for finding similar artists.