By way of comparison, I ran the numbers back in 2009 using a similar sampling technique: http://blog.unto.net/sampling-twitter.html http://blog.unto.net/sampli

By way of comparison, I ran the numbers back in 2009 using a similar sampling technique: http://blog.unto.net/sampling-twitter.html http://blog.unto.net/sampling-twitter.html At the time, I estimated roughly 1,200,000 active and connected users on Twitter. This author currently estimates around 80M active users (as of mid-2012), or a 80x increase over three years. Note that both samples considered "active" to be someone who posts, which is quite a bit stricter than the (reasonable) definition of consumption that the industry has been stabilizing on. Neither of us knew how to account for spam/fake accounts, which must represent some non-trivial part of the ecosystem (at least judging from the followers my own dormant account continues to attract: http://twitter.com/#!/dewitt/followers http://twitter.com/#!/dewitt/followers). I found it interesting, though in hindsight not surprising at all, that the average length of username is also going up over the years.