I joined Goodreads this weekend. I had heard of it, but not gone down that road before.  

Google has now splashed into the social networking pond (hmm, ocean really) with its OpenSocial initiative. OpenSocial joins the set of free tools from Google that software developers can use to embed functionality in their web sites. Unlike other Google tools, OpenSocial doesn’t open up things Google like its Maps or News. Instead, the goal is to allow developers to get at social networking information that more and more of us have up on sites like myspace or Linkedin.