A decentralized digital currency without a central bank or single administrator, Bitcoin was released as an open-source software created as a reward for a process known as mining. Bitcoin offers the promise of lower transaction fees than traditional online payment mechanisms and is operated by a decentralized authority, unlike government-issued currencies. As the earliest cryptocurrency to meet widespread popularity and success, Bitcoin has inspired a host of other projects in the blockchain space. Bitcoin charts high on popularity, and has triggered the launch of hundreds of other virtual currencies collectively referred to as Altcoins.
Every 4 years, the number of new bitcoins mined every goes down by half.