Introduction to the ASP.NET Web API

http://stephenwalther.com/blog/archive/2012/03/05/introduction-to-the-asp-net-web-api.aspx

With the release of ASP.NET 4 Beta, Microsoft has introduced a new technology for exposing JSON from the server named the ASP.NET Web API. You can use the ASP.NET Web API with both ASP.NET MVC and ASP.NET Web Forms applications.