A lot of us are trying to figure out how much attention we should be paying to Twitter--the company, our own feeds, the feeds of those we follow.  The big questions have to do with Twitter's impact.  Is it reaching people in a meaningful way?  Is it an effective marketing tool?  And just how many people can you reach with it?  When Pear Analytics came out with its study of Twitter users, we felt that this chart explained a lot about what we were seeing in our own Twitter experience:

But the ease of use, the speed with which we could learn about events, and the access to more thinkers, writers, even companies keeps us thinking that Twitter has great utility. So we're on the lookout for the best analysis of how many users Twitter has compiled. According to the company, there are 175 million Twitter accounts.  But that is accounts, not users.

Nicholas Carlson of Business Insider recently tried to get an estimate on the number of active users.  After recruiting a friend who understands Twitter's API, Carlson made some interesting findings:

At Facebook, a company source tells us, they believe that a user is not going to end up sticking around unless they make friends with 10 people.

So let's say an "active" Twitter user is someone who follows at least 10 other accounts.

How many such "active" Twitter users are there? Our source's API data shows that there are 56 million accounts on Twitter following 8 or more accounts. There are only 38 million following 16, and just 12 million following 64.

Your author, by the way, follows 700 people. There are only 1.5 million accounts on Twitter following 512 or more accounts.

Read How Many Users Does Twitter REALLY Have? here.