Are crypocurrencies safe/stable? Where does the value of a bitcoin come from? A note has value because its amount in gold [a small portion of it anyway] is held in reserve, right? When a bitcoin block is created, how is it a real, valued sum of money? And why would someone use bitcoins over, say, USD over a paypal account? What benefit does the bitcoin user have [with his paypal equivalent I guess] over the USD user? And where are crypotcurrencies headed? Will the mining bubble burst a few times and the diminishing returns shut it down where bitcoins are used...as what? And valued by and for what?