Mellowads + U-ads didn't accept me because of to low traffic/alexa rank.
I saw quite a lot faucets using these two. But unless you get that alexa rank you need to make use of other ad networks.
I think it would be cool to have often updated site about how to run a faucet. I would love to see a site with detailed infos about ad networks, how much is the best payout/timer and how to protect the faucet from bots. And also some real stats of a faucet with income + outgoings.
What do you think?