jtomm: Great post, thanks for the book citation. If the U.S. dollar were to really tank, I wonder whether the U.S. Government would ban using "Biitcoin as a currency. I believe that during the Great Depression President Roosevelt banned owning gold. Don't know whether that is a valid analogy. I know China has disdain for cybercurrencies. If only a very small percentage of citizens hold Bitcoin, banning it would not be a great political risk. What I am saying, I guess, is that I wouldn't go head-over-heels into cybercurrencies. Moderation is nearly always the best approach.