In the December 2008 survey, we received responses from 186,727,854 sites. This total has grown by 1.56 million sites since last month.
Apache shows the largest growth this month, gaining a further 2.47 million sites. Just over half of this growth is due to the net hostname growth at ThePlanet.com, which once again includes a large number of .pl domains. Many of these new sites redirect to another site hosted by ThePlanet.com, which appears to offer PornTube videos, but in fact directs visitors towards a site which Google believes to be malware .
Yahoo! Traffic Server shows another large gain since it was uncloaked at Yahoo! last month. This month's survey now finds 1.68 million sites running on YTS, which is used exclusively by Yahoo! as a reverse proxy and connection management server for a number of its services.
nginx shows the 3rd largest growth this month, climbing by more than 10% to reach 3.35 million sites. This server now has nearly 1.8% of the worldwide market share — an impressive feat, given that it is the work of just one man, Igor Sysoev.
June 2000 - December 2008
A more detailed list of servers is given here.