I agree with Tom regarding Bitzfree.
It can not be a Ponzi Scam when there is no option for investment.
It looks like a free faucet (with the source of revenue from ads) with additional games like 'hacking other users' etc ...
BTW, compliments for a great thread!
Ive been on Bitzfree for a while as well. They have a lot of people showing withdrawals on their facebook page.
They listen to their users on the forums and they do requent updates and stay active. So far my only issue is being hacked.
Produced over 700 Gh/s and am sitting on 400. Rip me.