Thanks for the link. I don't think it answered my question, but it did provide some new information for me. The biggest new question it raised was where it said that there will never be more than 21,000,000 bitcoins, and a link to a chart showing the number of bitcoins now in circulation is between 16,200,000 and 16,300,000. An arbitrary limit on the number of coins in circulation puts severe limits on the usefulness of the currency. The ability of central banks to adjust the total money supply is critical in managing a large economy.
I've never trusted bitcoin because of the unstable conversion rate. A stable value is critical for a currency.
But I'm still fascinated by it. I wonder how much bitcoin activity is used for nefarious transactions, and how much is just people who don't trust banks and don't want to pay tax on transactions. And for all its touted security, I wonder if it's really more secure than banks, which use dollars, which are much more widely accepted and exist both electronically and as cash.