after the recent up-and-down of the Bitcoin/USD exchange rate, I have been giving some thought on what could be the long-run value of a Bitcoin.
I think Bitcoin is appealing because it is fairly anonymous (not as anonymous as cash, but way more anonymous than a bank transfer), it is easy to transfer, and it provides a potential store of value (since its supply in every moment is known, and cannot be affected by governments or central banks).
One particular category of people that may like these caracteristics are illegal organizations. I don't think that the illegal activities will be the main use of bitcoin, but there are a lot of data about the size of the illegal market. So, for the sake of my back-of-the envelope calculations, let's look at the bitcoin use as a mean of exchange in illegal activities.
To give an idea, in March 2007, Mexican police seized 207 million USD in a single operation against drug cartels. If this money was stored in Bitcoins today, the value of a bitcoin should be now around 52 dollars (there are 6.5 millions BTC at the moment, trading at a price around 20USD, for a total value of 130 millions USD. Add to this number 207 millions and divide by 6.5 millions).
Again, transparency international estimates that the total amount of bribes paid world wide each year to be 1 trillion USD. Suppose that 1/4 of this amount was kept in Bitcoins at every moment (1 trillion is the total flow, we need some guesswork to establish the stock corresponding to this flow). The same calculation made before leads to a staggering 38000 dollars for 1 bitcoin!
On a less 'illegal' note, the total amount of remittances sent by immigrant to their own country in 2007 was $355 billion (world bank). Assuming that this number was the same for 2011, and that 1/4 of it were stored in Bitcoin, today the value of a bitcoin would be 13000 dollars for 1 bitcoin!
It is hard to say what the long run value of a Bitcoin can be, but I think it is definitely much higher than the current trading value.