The review of the FACEBOOK.NET open source library for use in developing Facebook applications and accessing Facebook APIs. The library is primarily geared around and optimized for developing ASP.NET-based Web applications, both FBML and IFrame-based Facebook applications through an intuitive API and small set of server controls. It does support the use of the Facebook API from desktop applications as well, and will eventually enable Silverlight application usage.
Facebook.NET
The library is built on .NET 2.0, but should run on future versions of the .NET framework as well. Applications using Facebook.NET can be written in either C# or VB.NET.

At the moment current stable build available for download is 0.3.0.0. It has 225KB size and includes FacebookNET.Desktop.dll, FacebookNET.dll, FacebookNET.Web.dll, several XML files and some simple Samples. At the moment it has than 20 000 downloads.

The library is still in early form (some APIs haven’t been implemented yet, there are only a couple server controls: FacebookApplication, and FqlDataSource at the moment, etc.) but the intent is to grow this over the course of building some Facebook applications, and through community usage/feedback as well.

Downloads available at Codeplex