These days we’re fairly used to big numbers, and this week one particular big number seems to have surfaced more often than might be expected.

The number 20 billion – roughly the same number of bacteria in a probiotic capsule – has been in the news 3 times in the past week alone.

£20 billion – the amount of money allotted by BP as the claim fund for the Deepwater Horizon oil spill.

£20 billion – the current estimated cost of the London Olympic Games in 2010

20 billion – the number of tweets which have been published on Twitter since its launch in March 2006.

Of the three, the only bit of good news is of course Twitter’s success, and it seems incredibly that we’re already talking about passing the 20 billion mark, which happened on Sunday. Sadly the actual 20 billionth Twitter lacked a fanfare, roughly translating as ‘So that means the barrage might come back later all at once.’ Indeed.