In the March 2013 survey we received responses from 631,521,198 sites.

Microsoft showed a noticeable gain of 9M sites this month, increasing its market share by 1.42 percentage points to 18.01%. Much of this growth was seen at Go Daddy, which alone gained 2.6M sites powered by Microsoft web servers. Microsoft also fared well amongst the top million busiest sites, where its market share grew by 0.74 percentage points to 13.60%, increasing its narrow lead over its closest rival, nginx.

More than 130,000 of the sites in Netcraft's survey are hosted on Microsoft's Windows Azure cloud platform, but not all are running Microsoft web servers: Since Microsoft Open Technologies launched its VM Depot preview in January, more than 100 ready-to-use images have been added to the community-driven catalogue of virtual machines. This makes it easier for customers to deploy Linux-based images running preconfigured applications and frameworks such as WordPress, Joomla!, Drupal, Django and MongoDB. The majority of these images are based on Ubuntu Linux, and many of them use Apache and PHP to serve their content.

nginx also saw a reasonable gain in market share this month, with an additional 4.4M sites taking its share up by 0.68 percentage points to 13.53%. The most recent development release of nginx (1.3.13) introduced support for proxying WebSocket connections – an HTML5 technology which provides full-duplex communications between a browser and a web application over a single TCP connection. WebSockets are supported by all modern desktop browser software, for which the protocol specification defines two URI schemes: ws: for unencrypted connections, and wss: for secure ones. The development of WebSocket support in nginx was sponsored by CloudBees and Apcera, who will both be making use of the new feature in their own services.

nginx performed less well amongst the top million sites, where it had looked set to overtake Microsoft this month. Instead, a net loss of 910 nginx sites resulted in its share falling to 12.72%.

For more information see Active Sites