There's an interesting article at Washington Post. Here's the first bit:

Dueling Viruses Are Latest Computer Pest
Consumers and Businesses Caught in the Crossfire as Hackers Take Aim at Each Other

By Mike Musgrove
Washington Post Staff Writer
Thursday, March 4, 2004; Page E01

The programmers behind the ongoing wave of computer worms and viruses hitting the Internet are starting to take aim at each other, and consumers and businesses around the world are getting caught in the crossfire, security experts said yesterday.

In the space of about three hours early Wednesday morning, five new variants of widespread bugs MyDoom, Bagle and Netsky were spotted roaming the Web. And, in a new twist, the unknown virus writers have gotten into what amounts to a shouting match, by placing insults and threats against each other in the coding of the latest versions of their wares.