And when you break it down further, it equates to each customer having ~15 BTC each or less, assuming 622,000 total bitcoiners. I guess about $5M cap is something to be in awe about.
I am impressed with the 311K figure regardless of what each/any have on account. It's possible there's a million bitcoiners in the wild, considering a rough extrapolation.
Don't break it down any further than that or who knows what dirty secrets you might discover. Like you know, that the difference between pre-hack MtGox (when they had an imaginary account credited with half the Bitcoin in circulation that somebody gained access to) and the post-hack MtGox is limited to better security for the fake self-trading account.
And one of those accounts consists of Bitcoinica's coins of which is not supposed to be touched.