According to Netcraft’s latest monthly web server statistics, Windows gained 4.7% share, while Apache dropped 5.9 percentage points. It was the largest monthly shift ever from one web server to the other, according to the company.

That said, Apache is still well ahead of Windows, with 62% of all hosts surveyed, versus Microsoft’s 25%.

Netcraft’s survey measures the number of hostnames running each platform. The shift to Microsoft was caused by Go Daddy, the largest domain registrar, agreeing to host all its customers’ parked domain names on Windows, rather than Linux.

Parked domains are placeholders for when a domain is not in use. Go Daddy moved 3.5 million such domains to Windows boxes. People running actual working web sites with Go Daddy can choose to host on Windows or Linux.

Netcraft said there are now over 80 million websites on the internet, an increase of 3.1 million over the course of the month. This means the web doubled in size, as measured by hostnames, in the three years since April 2003, the firm said.