Regarding the 2010 Twitter statistics, the most interesting news is not that Twitter has been growing further. What is really exciting about the key findings of Sysomos latest study is the fact that overall the number of Twitter users that reveal some personal information about themselves has doubled.
In 2010 69 % of all users gave personal information in their bio. (2009: 31%)
In 2010 82% of all users provided their followers with a name. (2009: 33%)
In 2010 73% provided location information. (44% in 2009)
In 2010 45% submitted a web address. (22% in 2009)
There may be two reasons for that:
1) Twitter is a maturing medium, which means: step by step people are upgrading their twitter presence and fill in data you may disregard or find unnecessary at the beginning or during a test phase.
2) Secondly I think that Twitter has finally become a relevant channel for personal as well as business networking. It isn't a channel for nerds anymore, it has become a channel where you do serious business. And serious business means that you have to identify yourself, brand yourself and provide your (potential) partners with background information.
That's the reason why I'm pretty sure that in 2011 we won't see discussions like "Will Twitter survive the year XXXX" anymore. Twitter is there and Twitter will stay.