no real viruses but greynets are the danger
the greynetdanger level has been set to a scale of 7 out of 9 by the consortium facetime that monitors and informs about the P2P, IM and chatware application dangers and this based on its research (how much of it is fearmongering to sell stuff is another thing ...... but if all these consultants of all these big names wanna lose their face at some time ..... )
what are greynets ? It is more or less the same discussion between what is a virus and what is spyware and what is adware (and all the debates and trials surrounding this).
There is no doubt that botnets are controlled by mobs and digital bandits and are a virus to stop. So Greynets are networks made by adware-spyware or rogue applications (that do things that aren't evident to the user before installing) and use the same techniques as botnets and applications like P2P and IM to pass firewalls and to be not discovered by all kinds of securityware.
one example is aurora adware bundle (they do bundle all spyware-adware nowadays, sometimes with even installers, why earn money with one install if you can install them all)
tip 1 to know if you are infected by this greynet look for Poker3.exe and MC-58-12-0000080.exe on your system (start, search) and if you are redirected to brazilian websites (block .br) than you have it
tip 2 the aurore uninstaller http://www.mypctuneup.com/uninstaller_exe.php
but to make a long story short. Your contacts in your messenger or chatprgr will get a message from you with a link (if they are stupid enough to click on it, they get infected). The networking aspect in it is that they are updating themselves, getting new adware and links and so on
more to come on http://spyware.skynetblogs.be