"Bitcoin," says
the project's website, "is a peer-to-peer currency. Peer-to-peer means that no central authority issues new money or tracks transactions." Wikipedia offers a readable explanation of the
underlying technology. In (very) short, Bitcoin uses a distributed database and public key encryption to allow users to reassign ownership of units of Bitcoin currency (BTC), and does so in a way that can keep the user's identity private. Bitcoin isn't yet accepted the way credit cards are, but it's
more than theoretical. You can buy (some) things with Bitcoin, and
trade the currency itself.
Now, you can ask question about Bitcoin of Amir Taaki, a developer of client interfaces and stock trading software for Bitcoin, and owner and operator of trading exchange
Britcoin.co.uk. Amir requests that questions focus not "so much on the mining (too many people get focused on that
when it's a minor aspect of Bitcoin) nor simple technical questions (people can
go find that info themselves on Wikipedia/the forums/sourcecode)," but rather on the harder-to-answer questions. Reading some of the related stories listed below may give you ideas on what those are. Standard
Slashdot Interview rules apply: ask as many questions as you want, but please keep them to one per comment. Amir will get back with his answers.