Bitcoin is a decentralized digital currency based on an open-source, peer-to-peer internet protocol. It was introduced in 2009 by a pseudonymous developer, Satoshi Nakamoto. Bitcoins can be exchanged through a computer or smartphone locally or internationally without an intermediate financial institution. In trade, one bitcoin is subdivided into 100 million smaller units called satoshis, defined by eight decimal places.
Bitcoin is not managed like typical currencies: it has no central bank or central organization. Instead, it relies on an Internet-based peer-to-peer network. The money supply is automated and given to servers or “bitcoin miners” that confirm bitcoin transactions as they add them to a decentralized and archived transaction log approximately every 10 minutes.
Text via Bitcoin Wiki