Social Influence Measurement Startup Klout Passes 2K API Partners

Klout, a startup that measures influence on Twitter, LinkedIn and Facebook, has hit a significant milestone today—2,000 developers using the startup’s API. That’s up from 250 developers last year.

Klout evaluates Twitter, LinkedIn and Facebook users’ behavior with complex ranking algorithms and semantic analysis of content to measure the influence of individuals and topics around the web. On Twitter, Klout’s influence score is based on a user’s ability to drive action through Tweets, Retweets and more. On Facebook, Klout will examine how conversations and content generate interest and engagement, via likes, comments, and more, from the network’s 600 million-plus users.

Companies using Klout’s API include Radian 6, About.Me, ExactTarget, The Huffington Post, Seesmic, Gnip, Gist and StockTwits. Currently Klout is doing more then 500 million API calls per month and is adding more than 5 API partners per day. For some perspective, Twitter sees more than 6 billion API calls per day.

And armed with $8.5 million in new funding from Kleiner Perkins, Greycroft and others, Klout is trying to build a big company out of measuring influence online. It looks like the startup is on the path to accomplishing this goal.