DotNetNuke or DNN is a free, open source website builder and content management system based on the .NET framework. It was written in VB.NET, initially and has now shifted to C# since version 6.0.
Umbraco is an open source content management system (CMS) platform used to publish content on the internet and intranets. Written in c#, it s a platform deployed on Microsoft based infrastructure.
mojoPortal is an award winning open source, cross-platform, content management system (CMS) for ASP.NET written in the C#. It supports a variety of plugins and has built-in support for, forums, event calendars, blogs, photo galleries and an e-commerce feature too. It is a highly stable and scalable CMS that is a hot favorite amongst developers due to its ease of use.
Kooboo is a flexible and extensible open source CMS based on Microsoft .NET MVC4. It offers a perfect balance between business processes, content, and design. It is a single CMS solution that enables to set up and manage multilingual websites on one computer.
SiteFinity is an ASP.NET based content management platform used for the development of online applications, commercial websites, community portals and intranet applications. It’s really not rocket science and one of the easiest things around that even a non technical person can work on!
nopCommerce is open source ecommerce software that contains a catalog frontend and an administration tool backend. It is a fantastic fully customizable shopping cart that is highly stable and easy to use.