Not a scam as such but click on anything they advertise and you'll find a scam. One big one on their page is "anonymous" will hack double spends for you and you will get ten times what you give them etc. They are making a huge amount from their adverts and a miniscule amount gets passed on the the people that keep the place going.
Bitzfree.com is terrible. I worked my way up to $130 income then it just suddenly dropped to £13. I wasted a lot of time and money just for them to screw me over. It is riddled with highly intrusive ads and they are well known for just cutting users off after they get a decent hash rate. Avoid it like the plague.