Klout is a website and mobile app that uses social media analytics to rank its users according to online social influence via the "Klout Score", which is a numerical value between 1 and 100. In determining the user score, Klout measures the size of a user's social media network and correlates the content created to measure how other users interact with that content. Klout launched in 2008.
Klout uses Bing, Facebook, Foursquare, Google+, Instagram, LinkedIn, Twitter, YouTube, and Wikipedia data to create Klout user profiles that are assigned a unique "Klout Score". Klout scores range from 1 to 100, with higher scores corresponding to a higher ranking of the breadth and strength of one's online social influence. While all Twitter users are assigned a score, users who register at Klout can link multiple social networks, of which network data is then aggregated to influence the user's Klout Score.