With more than 3.9 million hostnames, Germany's 1&1 is the world's largest hosting specialist. The overwhelming majority of its sites are powered by Linux, with just 88,000 of 1&1's hostnames on Windows, almost all of them in its German operation. 1&1 showed its marketing muscle with its entrance into the U.S. market earlier this year, as it has quickly gained more than 147K hostnames and 78K active sites.

Given that success, 1&1's Microsoft marketing campaign figures to provide additonal market momentum for Windows Server 2003, which is already receiving a substantial push from Microsoft. In the May Web Server Survey, 2.1 million hostnames were identified on Windows Server 2003, with a gain of 390K hostnames from April. Around 50 percent of these are new sites, while just under 100,000 have migrated from Linux.

1&1's cheapest Windows plan offers 500 megabytes of web space, 5 gigs of monthly transfer volume and up to 50 POP boxes for the $4.99 monthly price.