The Windows Defender Blog
Finally, someone in marketing decided that a product name could be both functional and cool! Windows Defender has to be the best product name since, oh, um, Proxy Server 2.0. Sort of.
The Antimalware team (I read it as "animalware" twice, curse my eyes) have just started blogging, so go check 'em out. And they cover more than just Defender (kudos to anyone that calls the next anti-malware product "Asteroids").
