I agree both are "greater fool" schemes. The only real difference is some of them are started by one (or a few) people to make money. I. e. Ponzi, and the invertors of bitcoin, and originators of chain letters,* (many of them) etc. are in the same group as they do have your "nefarious conspirator(s)." I refer to ALL this group with founders hoping to get rich as "Ponzi Plans." Teulipmania, Florida land bubbles, (there have been at least 4), vinyl disk music, (or baseball card) collectors, etc. which have no "founder(s)" are in in a different group. Bitcoin's founders not only are getting rich but literally are "making money" too. Ponzi only got rich, until the collapse. Both these types of greater fool plains ultimately collapse, either when no greater fool can be found or the government makes them illegal (as Chain letters are already and bitcoin will be when it cuts significantly into the government's revenue - "senoriage profit" of >95 cents on each dollar it prints. Vinyl disk music collectors are now no more than two generations from collapse as by then there will be no functional machines that can play the music. Baseball card collectors probably will be finding greater fools (some die each year, but are replaced) until soccer (or another team sport) has replaced baseball and no one even remember the rules of baseball, but it will collapse someday too, as there is very little intrinsic worth in small pieces of thin cardboard. * I think only chain letters that ask you to send money are illegal, but perhaps all are as Post Office loses more money, the more mail there is. The one I like best asks for a service, not money. It goes like this: Add your address to bottom of the list and remove the top one so list remains 4 long. Then send letter, with your name at the bottom, to four of your closest (live near you) friends. After that, you go after dark on 4 consecutive days, to the four address sent to you and shit on the lawn there. (Don't be embarrassed - many will doing the same.) Then after a few days, for couple of weeks, if no one breaks the chain, your lawn will be fertilized for free by 256 people! PS - Unlike many chain letters this one can continue forever - a few months from now, you may get the same opportunity to help others ecologically again.