A while back, I used to maintain a Frequenty Asked Questions file on "malware", or malicious software, which included viruses, trojans, spyware, adware, and all sorts of other nastiness. I kept myself up-to-date on the latest things that were showing up, and the methods to get rid of them.
I realized a few years ago that the field was changing, that malware was no longer being written by angry teenagers, but was instead starting to be written by professionals who had a financial stake in the success of the "product". It became harder and harder to keep up with the flood of crap, and eventually I stopped maintaining the FAQ, preferring to leave things up to the professionals.
Well, the future of malware is here, and it's very ugly.
Wired: Gathering 'Storm' Superworm Poses Grave Threat to PC Nets
Old style worms -- Sasser, Slammer, Nimda -- were written by hackers looking for fame. They spread as quickly as possible (Slammer infected 75,000 computers in 10 minutes) and garnered a lot of notice in the process. The onslaught made it easier for security experts to detect the attack, but required a quick response by antivirus companies, sysadmins and users hoping to contain it. Think of this type of worm as an infectious disease that shows immediate symptoms.
Worms like Storm are written by hackers looking for profit, and they're different. These worms spread more subtly, without making noise. Symptoms don't appear immediately, and an infected computer can sit dormant for a long time. If it were a disease, it would be more like syphilis, whose symptoms may be mild or disappear altogether, but which will eventually come back years later and eat your brain.
I am not looking forward to dealing with this crap on a regular basis.