I have recently compiled a database with some interesting twitter stats (this raw data you can also access here). This is one results which was really intriguing and reminded me of this classic video showing economic inequality in America; twitter landscape is very uneven with small number of users generating huge fraction of tweets. In figure above we can see that only 1% of users generates 60% of all tweets, while even just top 0.1% users are responsible for around 19% of all tweets. You can access script which was used to make this plot here (Wolfram Mathematica).