There are now more than 80 million web sites on the Internet, as the April 2006 survey received responses from 80,655,992 sites, an increase of 3.1 million hostnames from March 2006. The web has doubled in size in the past three years, as the survey hit the 40 million mark in April 2003.

This month's survey brings one of the largest one-month swings in the history of the web server market, as Microsoft gains 4.7 percent share while Apache loses 5.9 percent. The shift is driven by changes at domain registrar Go Daddy, which has just migrated more than 3.5 million hostnames from Linux to Windows. Go Daddy, which had been the world's largest Linux host, is now the world's largest Windows Server 2003 host, as measured by hostnames. The company said it will shift a total of 4.4 million hostnames to Windows Server 2003.

Technology trends among registrars have a large impact on web server market share, as each registrar hosts large numbers of parked domains. Microsoft's last major upward surge in market share in 2001-02 was boosted by migrations at Register.com and VeriSign. Go Daddy is the second huge registrar to shift its sites to Windows Server 2003, following the lead of enom. Among other major registrars, 1&1 Internet, Dotster and Register.com host on Linux, while Network Solutions uses Solaris.

"It was clear from all of the testing we’ve conducted that Microsoft provides an efficient and scalable operating platform, while also providing the performance needed to handle our extraordinary growth," said Warren Adelman, president and COO of Go Daddy.

Michael van Dijken, Microsoft's Marketing Manager for Hosted Solutions, noted that Go Daddy's migration to Windows Server 2003 follows announcements of expanded relationships between Microsoft and several other major hosters, including Web.com (Interland), Verio and Rackforce. "We've seen a significant amount of traction in the past two months," said van Dijken.