As much in the high tech criminal world, it is a complicated layering of information gathering/selling. They make your puter a 'zombie' where you are unaware of it being used to send out THOUSANDS of spam emails. It's a way of hiding their tracks. And this is only ONE of the things they do to exploit unguarded computers.
I also marvel at all this 'talent' being wasted in negative actions. Imagine if it was all focused on positive and productive projects...