Umbraco

Umbraco is the friendliest, most flexible and fastest growing open-source .NET CMS in the world. It is used by more than 500,000 companies and web solutions around the world, from small business brochure sites to complex multilingual corporate websites. Umbraco is the most mature and versatile open-source CMS on the .NET platform with a high degree of flexibility and an intuitive content editing interface for end users. Constantly improving, and with a user community of over 200,000 people, Umbraco is the first choice of more web professionals every day (~1,000 installs/day). Umbraco is cloud friendly and its SaaS solution, Umbraco Cloud is built on and backed by the Microsoft Azure platform.