A faucet is a site that allows people to earn bitcoins by completing simple tasks, such as solving CAPTCHAs, viewing a webpage for a specified amount of time, viewing ad content, even playing games.
The payout from each faucet task is generally quite small, but over time as you accumulate bitcoin currency through multiple tasks, and as the value of the BTC increases relative to other currencies (which it is expected to do), the earnings from bitcoin faucets could be substantial.
