Link found in the annals of Reddit, I think I may be spending a lot of time in the near future grokking bitcoins.
So this probably isn’t a case of one Bitcoin user sending $150 million to another user. Instead, Bitstamp was perhaps reshuffling its own funds, just as a bank might move stacks of $100 bills from one vault to another. Presumably, most of those 194,993 bitcoins belong to Bitstamp users who have deposited them with Bitstamp to facilitate currency exchanges.
