Bitcoin, an attempt to establish a new “peer-to-peer” virtual currency is described in an article in The Economist of June 16, 2011.
One can accept the need to search for new ways of creating money. I believe the recent financial crisis was in part a failure in the way in which our economy currently creates money. (Money is created when bankers make loans, subject to a multiplier effect from the requirement to maintain reserves. When a whole lot of loans went bad this decreased the money supply, again with a multiplier effect. With a suddenly decreased money supply, the economy went for a loop.)
One of the problems with the bitcoin system is the quantity of money available is strictly controlled according to a formula.
I have always liked the quantity theory of money which states that MV=PQ where M is the money supply, V is the velocity at which it changes hands, P is the price or price index and Q is the quantity of goods and services produced.. Therefore as Q goes up (or down) there also need to be changes in at least one of the others. If we want prices to remain constant, then we need a way of creating money such that the supply can easily be varied according to the quantity of goods and service produced.