~Why They Pay~
Advertisers are always looking for people to try their products, write reviews, and fill out surveys/ offers. Do Not Calls were put into effect a little while back, which stopped Advertisers from calling you at home, asking for "a minute of your time". Instead, these companies pay (GPT Sites) for people like you and me to sign up, and take offers/ surveys, giving them reputation, which in turn, makes them money. They pass this money on to GPT sites to recruit people to take surveys/offers, and GPT sites (like the ones listed below) pay you to complete these surveys/offers.