In order to properly use this faucet, you'll need a bitcoin wallet address for your winnings to be sent to. If you do not already have a wallet, one can be easily obtained by visiting https://bitcoin.org/en/getting-started and going to "Choose your wallet." When you have a wallet, you'll have a corresponding receiving address that you can use to have bitcoin sent to you.
On this site, when you enter your address, the bitcoin you receive will temporarily be sent to Faucetbox.com. After amassing a certain amount on this and other faucets associated with Faucetbox, Faucetbox will send your bitcoin to your wallet. If you do not know how much bitcoin you have on Faucetbox.com, you can use their "address checker" to see how much you have as well as a ledger of all deposits from faucet sites.

What is bitcoin?
Bitcoin is a digital currency, published in 2008 by Satoshi Nakamoto, though the identity of Satoshi Nakamoto is still unknown and heavily debated. The system behind bitcoin is peer-to-peer without the need for an intermediary or administrator, such as banks, so this currency is effectively decentralized. These p2p transactions are verified on the "blockchain", a network of nodes run by bitcoin users. The blockchain acts as a public ledger of all transaction activity.

How are bitcoins created?
When bitcoin users utilize their computers to verify transactions on the blockchain, bitcoins are created and distributed as a reward for their time and efforts. When normal p2p transactions are made, they are batched together into "blocks". These blocks are advanced algorithms that are solved, or "mined", by the computation power of the users mentioned above. The user(s) that complete the algorithms are rewarded 25 bitcoins.

Can an unlimited amount of bitcoin be created?
No, it is important to note that over time, this reward of 25 bitcoin will halve every ~4 years. In mid-2016, this reward will halve to 12.5 bitcoin and this process will continue every ~4 years until sometime between 2110-2140 when the maximum number of bitcoins will be distributed of 21,000,000. It is because of the finite number of bitcoins that the digital currency has value.

For complete information on bitcoin, please go to the Wikipedia