Klout
Klout helps people who want to be great at social media measure their online impact
Get a Klout User's Influencees
Find the people that are influenced by a specific Klout user ...
Get a Klout User's Influencers
Find the people that influence a specific Klout user based on...
Get Interest Topics of Klout User
Find the topics a user is interested in, given what they post...
Get Klout ID from Twitter Username
Given a Twitter Username, find that person's ID on Klout....
Get Klout Score for User
Given a person's Klout ID, find their Klout influencer score....