An easy and engaging read that helps you get past the "bitcoin is just a currency that will probably disappear" conversation... Like I had last night with a mate over several pints..
It's becoming increasingly clear that Satoshi's creation has the potential to change how much of commerce itself works, and for reasons not even many Bitcoin fans realize. By many accounts, Satoshi came up with a real-world solution to a longstanding computer science paradox known as the double-spend problem, or the Byzantine General's problem (the professor who named it explains why he did so here). The challenge is how to send and receive money online without the need for a trusted third party, such as PayPal, ensuring that the same digital credit standing in for the amount being exchanged isn't being spent twice. In the real world, this problem gets avoided with cash, which is quite difficult to counterfeit. In practice, digital counterfeiting is much easier. Satoshi's solution was what has become known as the blockchain: a ledger of all transactions owned and monitored by everyone but ultimately controlled by none. It's like a giant interactive spreadsheet everyone has access to and updates to confirm each digital credit is unique. It is this technology that programmers are now working to deploy for uses that go far beyond Bitcoin.