About Microsoft IIS
Internet Information Services (IIS) is an extensible web server created by Microsoft, formerly known as Internet Information Server.
From ASP.NET to PHP, IIS provides a powerful and flexible Web server for the world's most popular Web applications such as Umbraco, WordPress and Drupal. ASP.NET hosting is even more simple and powerful, with deep integration directly in the request processing pipeline, configuration system and management console.
IIS is built with a completely modular architecture, on top of rich extensibility APIs. IIS modules can easily be added or removed and built-in components can even be replaced by custom modules.