I remember back in the day there were viruses. Sure, they would be annoying: perhaps they would mess up your boot sector, or they would spam your friends that used hotmail /outlook, but not anything major. Whenever I read an article warning of a rising electro-viral menace, I used to think to myself “man, security companies are all up in arms over nothing”.
Things are different now: http://www.securecomputing.net.au/News/160867,gumblar-botnet-on-the-march-again.aspx
Botnets collaborating? Leveraging exploits and holding doors open for each other? Dang. Glad I run linux 🙂