We are paid monthly and I have been here for 3 months (see my profile) - I enjoy posting and the money is a plus point too, but do you think I would still be here if the money part was a hoax? No. There´s your proof!! Enjoy!
I doubt they would put this much emphasis on your earnings on the site, if they didn't intend to pay you.
Either way, it's not like you are really losing anything. It's a good way to blow time, and isn't costing you a dime.