The Open Source content management system SilverStripe runs on the Windows IIS server as well as all Linux web servers. Read this detailed case study published on the Microsoft website in March 2009.
The benefits of SilverStripe supporting Windows Server
"SilverStripe has experienced a number of benefits since incorporating support for Windows into its CMS software. While the updated technology has only recently been released to the community, already it has created new commercial opportunities for SilverStripe and helped the company secure a substantial web project in the competitive Government sector. In addition, the SilverStripe CMS for Windows has been included in the latest version of the Microsoft Web Platform Installer, exposing the technology to hundreds of thousands of potential users worldwide."