] According to Tubul, his group controls 450,000 "Trojaned"
] systems, most of them home computers running Windows with
] high-speed connections. The hacked systems contain
] special software developed by the Polish group that
] routes traffic between Internet users and customers'
] websites through thousands of the hijacked computers. The
] numerous intermediary systems confound tools such as
] traceroute, effectively laundering the true location of
] the website. To utilize the service, customers simply
] configure their sites to use any of several domain-name
] system servers controlled by the Polish group, Tubul
] said.

According to the article, this may have been one of the original purposes of the Sobig worm.

Wired News: Cloaking Device Made for Spammers