Fareed Manjoo wrote in Slate that Tweeting a protest against a company has more success when you have more followers and are therefore perceived as having more clout. However, the number of followers is less important than who the followers are--the President's Daily Brief is written for a select audience, but one with a lot of clout.
Seth Godin points out that the "web" knows how much "clout" we have and how much are followers have. It knows if our tweets are retweeted, if our followers have lots of followers, and which of our ideas are amplified. Each of these bits of information is hidden in a different place, but they could be aggregated together. Whether we like it or not, someone is going to figure out how to do this.
Are you ready to have your clout measured? Would you pay to have that information on your followers? What about your competitors?