Several anti-virus companies have discovered messages embedded in worms which are directed to the authors of other worms. Variants of worms are being created in just days with messages to slag the other worm writers off.
For example, a message in Bagle.j says: "Hey,NetSky, f*** off you b****, don't ruine our bussiness, wanna start a war?" Today Netsky.f appeared and had lines stating "Skynet AntiVirus --Bagle -- you are a looser!!!"
Command believes worm writers are battling for supremacy over computers they have compromised. Some Netsky worms destroy versions of Bagle worms that it finds on peoples' computer systems. Security firms have been busy monitoring each new worm. Source