Composite C1 is a fully featured - free open source - web content management system developed for and by web professionals building websites. End-users maintain the website content on a daily basis. The user interface is very functional and task oriented and enables users of varying technical skills to complete tasks and cooperate using familiar tools. Developers are highly empowered and able to control website look and feel down to minute detail. Source code: http://compositec1.codeplex.com/ Features:

Multilingual, UNICODE support Multiple document interface Publishing workflow Content security WYSIWYG editor XHTML compatible XSLT developer tooling .NET 4 and ASP.NET 4 based Transparent XML and SQL Server support via LINQ Side-by-side support for both ASP.NET Razor, ASP.NET Web Forms and ASP.NET MVC Support for templating using plain HTML, ASP.NET Razor, ASP.NET Master Pages and XSLT Run on Internet Information Services (IIS) 6, 7, 7.5, 8, WebMatrix, Visual Studio 2010/2012, Windows Azure Support for Mozilla Firefox, Internet Explorer, Google Chrome. Firefox users have spell check features. (this list is not exhaustive)

Add-ons (C1 packages):

Content versioning Newsletters Extranet Page comments Issuu reader RSS / Twitter / YouTube feed readers XML to SQL Server migration Google Search (CSE) integration Microsoft Search Server integration Package Creator Data Forms Renderer ASP.NET MVC Player Social Media integrations (Facebook, Twitter, Google+) (this list is not exhaustive)