"To sum up my opinion of this tool, it's beyond useless. Not that I ever planned to, but the last thing I'll ever do now is fill in more of my profile or join more groups."
Here's what Michael is missing. A major concept in social media is "authority", that is the "power" of a user or person online. A comment or post online from a user with high authority is something to pay more attention to than a similar post with lower authority.
The number of friends you have and your engagement with a social website is a good way to measure authority. This is what Facebook Grader is trying to do. Twitter Grader already does this well - the database contains over 1 million users and I submit that your Twitter Grade is an excellent measure of your authority on Twitter. Twitter has only 5 million members, but Facebook has over 150 million. So, the next step is to try to build a measure of authority on Facebook. Today there is no way to do that. But I think Facebook Grader has a chance to do it... in the future (we have some work to do).