Just out of curiosity, does anyone happen to know of any documented examples of a botnet being used for something more interesting than just sending spam or DDoS?
There are good botnets and bad botnets. Good ones ask you if you want to join, bad ones don’t. Good ones are typically things like SETI at home, Folding at home, Great Internet Mersenne Prime Search, DES crackers, etc., and if you’ve got something good to do, people will help. People usually only set up the bad ones if they want to do something bad - it may be interesting the first time they do it, like a new flavor of DDOS, but it’s not usually doing the world any favors.