Microsoft made huge claims about the security of Vista, and has likewise crowed about the "amazing" rollout rate of their latest attempt at making an operating system.

Since the USA is the first place such high-priced fluffery rolls out, it follows that most of their Vista sales have been in the US. And, since most third-party security software doesn't work on Vista, the only security most Vista users have is whatever was built-in at Redmond.

You can see the results: Massive new botnets in the USA.