I'm very grateful to this site because I was earning my fist satoshies there long time ago. I had stopped using it when the better opportunities appeard but a month ago or so I heard that someone really won $200 in BTC claiming their faucet so I started using the site again and now I'm at 23k sats there. 
They have over 3 million registered users so surely they can earn from ads on their site.
Advertisement is the main source of income for any website and mainly faucets but i dont think google ads are allowed in faucets now a days as i have seen many faucets drying out once google started banning faucets because it is against their policy,since all the other major ones are down freebitco.in is one of the oldest surviving faucets and they are back in momentum after someone won $200 They have over 3 million registered users so surely they can earn from ads on their site.