What: Klout measures the influence of Twitter accounts by giving a score of between 0 and 100. Higher "Klout" numbers represent an account with a wide and strong sphere of influence.
The media measurement tool is free for most users. A paid premium version might launch this fall.
How: Klout uses more than 25 different variables broken down into three categories: true reach (engaged followers vs. spam bots, dead accounts, and so on); amplification probability (likelihood a message will be ...