A good explanation and history of Bitcoin, from William J. Luther at aier.org:
In hindsight, the rise of cryptocurrencies appears to have begun with the introduction of bitcoin in 2009. Earlier cryptocurrencies had been launched in the 1990s, but they failed to take hold. David Chaum’s DigiCash is widely thought to have been ahead of its time. Chaum founded his company at the start of the decade, well before the rise of e-commerce. By 1998, it had filed for bankruptcy. More generally, early “digital-cash firms made a fatal miscalculation,” Julia Pitta wrote for Forbes in 1999. “They figured, wrongly it turns out, that consumers would be leery of using credit cards on the Web and would demand tight security and ironclad privacy.”
It was not clear, at first, that bitcoin would be any different. Perhaps fearing the fate of e-gold creator Douglas Jackson, bitcoin’s designer(s) adopted a pseudonym––the now-famous Satoshi Nakamoto––and shared the upstart open source project in email to the Cryptography Mailing List on January 8, 2009. Nakamoto had circulated a white paper explaining the technical details a few months before. Congratulatory replies soon followed, but there was little indication that bitcoin would quickly become a household name. It was little more than a novelty discussed by a handful of programmers on the Internet.