answer:For the personal user it’s nothing more than vanity. However businesses (including the one I work for) use it, and here’s how it was explained to me at work. My company tracks Twitter and Facebook for hashtags and other mentions of the company’s name or products. Every post is looked at, and if it’s a complaint, a staff member will step in to assist. The Klout score is a measure of how important it is: a Twitterer with high Klout has lots of followers so a complaint on their feed will reach more people than a Twitterer with a low score. So Klout is used as one of the factors in determining the priority of a particular complaint.