A few more notes. I don't know exact numbers, but people from the beginning of bitcoin are surely hoarding a vast amount of bitcoins. They are like the central bank. If they decide to cash out, the currency collapses (maybe just temporarily). I don't like the idea of a random 19 year old controlling the value of my savings. Furthermore there seems to be a multi gigabyte transaction log already. It seems that everyone logs the whereabouts of all the coins, right now the market is small, but if it should become big, we'd have Terrabytes of logs sitting on each computer just to be able to do finance. Maybe my technical understanding is not correct, then someone can correct me, but it doesn't seem like Bitcoins can really scale to a global level.