We asked the people at Twitalyzer, an independent research firm, to study the question, and they came back with something called the Influence Index. It counts the number of times somebody’s Twitter name is mentioned by other users (including retweets, which occur when one user rebroadcasts another’s message). The Influence Index doesn’t merely measure who’s talking on Twitter, but it also measures how much someone is affecting the conversation. Look below at how low Lady Gaga’s influence score is, for example...
Among the discoveries: It helps to come from one of the four countries where Twitter is most popular — the United States, Brazil, England and Canada. That may explain why there are three unfamiliar names, at least to most Americans, in the Top 10: Stephen Fry (a British actor), Luciano Huck (a Brazilian television star) and Rafinha Bastos (a Brazilian comedian, #1).
Eric T. Peterson, the chief executive of Twitalyzer, points out that some of the most influential users also make a big effort to respond to much less famous people with personal messages. Kim Kardashian falls into this category. President Obama, as you may have guessed, does not.
One last thing: Twitalyzer’s public Web site doesn’t let people calculate their own influence scores.
But you can get your impact score, which is a 0-to-100 index that combines influence, number of followers and frequency of message writing.
Calculate Your Twitalyzer Impact Score
10 Most-Influential People*
4. Stephen Fry
6. Snoop Dogg
7. Barack Obama
8. Rainn Wilson
10. Huck Luciano
10 Most Followed People
1. Lady Gaga
4. Barack Obama
8. Katy Perry
9. Taylor Swift
10. Oprah Winfrey