I'm thinking of replacing the Bitcoin Faucet's reCAPTCHA with an AdsCaptcha -- instead of solving a CAPTCHA to help scan books, people visiting the site would be shown advertising which would help refill the Faucet with bitcoins.
My goal isn't to make money from freebitcoins.appspot.com, my goal is to make it sustainable without relying on donations. According to the AdsCaptcha folks, they expect advertisers pay anywhere from 1 to 20 US cents per CAPTCHA solution, depending on web traffic, how well the website fits their product, etc. The Faucet is currently giving out 0.05 bitcoins per visitor, which is 2 cents at current prices.
I would also like to gradually relax some of the anti-cheating measures I have in place that occasionally make it frustrating for non-cheating new users who "look like" people who are constantly re-visiting the Faucet (using proxies and new bitcoin addresses) to try to get more than their fair share.
One danger is that I implement AdsCaptcha, donations to the faucet stop, I find the revenue from AdsCaptcha is less than 0.01 BTC per visitor so that whole thing is even less sustainable than the current "somebody steps up and donates more when the balance gets low enough" model.
What do you all think?