IIRC Freebitcoin and Bitcoinzebra faucet both charge 0.01 BTC per ad per day. That is huge considering the amount of ads that they display on a daily basis. Mind you, they charge just for displaying the ad. If the site has a referral program, they may also use their own ID for referral commission as well. Even if they charge 0.01 / ad and there are 10 ads on their site every day (which seems to be the case) thats 0.1 btc / day and 3 BTC / Month, not including possible referral earnings. Also since freebitcoin offers a multiplier option, many people just go ahead and lose back the free satoshi that their earn. That goes back into their funds. They clearly had the first mover advantage and made huge profits due to the same! 
Where did you find info about 0.01 for day?
Info from freebitcoin: "Our advertising rates have been lowered by 50% to only $0.12 per 1,000 banner impressions."
Freebitcoin - $0.12 per 1,000 views - 1 view = 734 satoshi = $0.002 * 1000 = $2
they have 2 banners so 2*$0.12 = $0.24
$2 - $0.24 = $-1.76 - and this have to be covered from to ads from AdSense.. no way!
Bitcoinzebra - i don't want comment now.. I thin that they will be down soon.. (this is only my opinion)
