Here's something different for a blog that generally focuses on enterprisey technologies. A .NET guy in Denmark built a C# wrapper on Google's Social Graph API.  The Social Graph API exposes its data in JSON only; I guess it is designed to be consumed by web pages.  This dev put a C# wrapper together that can be used in any .NET app, including in code-behind in ASP.NET pages.

Check it out.

http://blog.madskristensen.dk/post/Build-your-online-social-graph.aspx