IIS is web hosting software by Microsoft. We do not run Windows IIS on our servers but support most the features of one and a WHOLE lot more. You do not have to have a Windows hosting provider if you usine Microsoft Windows on your PC. It is simply the software used to run the server. In 1996 the more popular featured web serving software Apache overpassed IIS and has been the dominant web server software since.
We run 64-Bit Enterprise Linux servers with Apache. For IIS compatibility we also support ASP.NET 2.0 and Sharepoint.