It’s a bit complicated to call it just a currency or just a commodity. Mining is only one part of it (the commodity part). The other part is as a currency.
On the commodity side, they are created at a predictable and limited rate. The more that are created, the harder it is to create more. The system is calibrated so that they will all be mined by some specific date, I think I saw 2050 or something. There is a max that will ever be created, but they can be divided into as small of pieces as you want.
In general, Bitcoin is trying to do for money what the Internet did for communications. Borrowing from http://bitcoin.stackexchange.com/questions/336/what-is-a-good-way-to-concisely-explain-bitcoin: “Email let us send letters for free, anywhere in the world. Skype lets us make phone and video calls for free, anywhere in the world. Bitcoin lets us send money to anyone online, anywhere in the world.”
From the same thread: “Bitcoin does everything you’d like a currency to do, and it doesn’t have any of the drawbacks associated with any of the other currencies available.”
I’ve seen it described as “a startup currency.”
I’ve seen it described as “a truly single global currency backed by the full faith of the world” rather than the full faith of an individual, country, or company.
I’ve also seen it described as “a real-life version of Sci-Fi’s ‘Credits’.”
As a techie futurist sci-fi geek it turns me on, but as an amateur no-nothing economist I’m not so sure what it all means.
