There is a link to the wallet block chain at the bottom of the page which lists all the fountain's transactions, no users have cashed out yet, but this is mostly because of the miner's fee, so people tend to save more before cashing out. There is currently BTC in the fountain wallet, and is able to handle any cash out that could currently be made. (The minimum cashout is now .002 BTC, and miner's fee .0005)
Looked at your blockchain page and there are a couple of payouts but it looks like you're not actually passing on the majority of the fee to the miners. You're only paying 0.0001 fee, but charging your users 0.0005. Is that intentional?
And it looks like the are separate transactions. Why not batch them up to minimize the fees for everybody?