It's not a cash in hand website, but it does offer rewards, and is legit. You sign up at mypoints.com, and they send you email offers. Everything from book clubs to flowers from FTD to Overstock.com. You don't have to actually buy anything; you get points just for reading the email and clicking the link there. If you do decide to purchase anything, you get bonus points.
If you're shopping online, go to the mypoints website first, then go to the online store of your choice, and you get points for each dollar spent. Some stores (like Barnes and Nobel, or Target) often offer extra or bonus points.
They also have a games page where you can play for cash, and get points per dollar spent.
They also have a credit card that you can use in everyday life to gain points for all your purchases. I don't have one of these myself, but I've seen them before (working in retail), and people have said they're very happy with them
All your points add up over time, and you can cash them in for gift cards for just about anything under the sun. In the last few years I've gotten cards for Target, Barnes and Nobel, and Starbucks, probably totaly over $100. I have a huge pile of points that I'm just waiting for the right thing to spend them on. You can even put points toward airline miles.
Just reading the emails means points pile up slowly. If you shop online they come in much faster. I buy any flowers or magazines or books by going to mypoints first, so the points do add up pretty quick.