Who posted 5 billion Tweets in 4 months?

The answer, it seems, is everyone. The total number of 140 character maximum messages posted to Twitter stood at 5 billion late last October (up from a billion the November before) but has leapt forward as the popularity of the micro-blogging system goes into overdrive and last night hit the magic 10 million messages milestone. Which means that in the space of just four months users of Twitter have posted a combined total of some 5 billion Tweets.