Number of Twitter users

One reliable source for the number of Twitter users is Twitdir. Twitdir reports the number of Twitter it already discovered on its homepage. As Twitdir is only capable of detecting Twitter users with a public profile, this number is a underestimation of the total number of Twitter users. I have been following the number of Twitter users reported by Twitdir for a couple of months by now. I made a graph showing the number of Twitter users according to Twitdir over the last seven months.


I want to make one prediction for 2007, more specifically regarding the number of Twitter users reported by Twitdir. I expect this number to reach 1 million before April 1, 2008.



By the way, as the percentage of Twitter users with a private profile is sometimes estimated at 10% to 15% Twitter will reach 1 million users even sooner, probably around March 1, 2008.