I created this presentation for my social media class last week, and I thought I'd share it here too.
Klout is a site that aggregates data from multiple social media platforms and measures your influence, resulting in a score.
If nothing else, it's interesting to just see what kind of social media reach you have so you can better understand how to use your influence. However, I imagine more casual users of social media will have little use for or interest in such information. It's definitely geared toward people who are actively involved online and interested in furthering their reach.