Lots of Twitter users have lots of followers. For instance, according to Twitaholic right now Lady Gaga has over 9.2 million; Justin Bieber has over 8.6 million; and Britney Spears, over 7.3 million -- just slightly ahead of Barack Obama. But new research published by the Association for the Advancement of Artificial Intelligence shows that simply having a large Twitter following isn't necessarily enough to make you especially influential. On Twitter, how many re-tweets or mentions a user attracts over time also are important ways to measure influence. This was a pretty big study. The international research team (here's the project site) examined nearly 55 million Twitter accounts that were in use in August 2009. These users were connected to each other by 1.9 billion social links. Over 6 million of these users were considered "active" in that they'd posted more than 10 tweets and had a currently valid screen name. In all, over 1.7 billion tweets were analyzed -- all the tweets ever posted by the nearly 55 million users being studied. The researchers examined three metrics of influence on Twitter: the number of followers, re-tweets, and mentions of Twitter users -- not direct re-tweets, but casual mentions More How to gain influence on Twitter?