Recommend study materials on social networking tools

Hi everyone,

I’m in the process of catching up on development tools and trends for social networking services and tools. For example FBML, OpenID, etc. I’m looking for APIs, popular services and anything else. Anything with an API or anything that seems to be increasing visibility or seems interesting to you.

Thanks for your help.

You should start with and ask questions in facebook developer forum.

I’ll definitely check out their forum. However can anyone else recommend any other resources or books?