The futures markets are characterized by the ability to use very high leverage relative to stock markets. Futures can be used to hedge or speculate on the price movement of the underlying asset. For example, a producer of corn could use futures to lock in a certain price and reduce risk, or anybody could speculate on the price movement of corn by going long or short using futures.
As Satoshi notes, bitcoin’s irreversible, trustless nature removes the need for any middlemen to mediate and broker the process of payments from one person to another. Middlemen (e.g. banks and credit card networks) inherently introduce overhead costs and inefficiency into the system, which make transactions — and micropayments in particular — more costly than would otherwise be the case.
Bitcoin is a digital currency, also known as a cryptocurrency, and is created or mined when people solve complex math puzzles online. These bitcoins are then stored in a digital wallet that exists on the cloud or the user’s computer. Because bitcoins are not housed in bank accounts, brokerage, or futures accounts, they are not insured by the FDIC or SIPC.