For those that are new to the get paid to surf concept, here is an explanation.
Advertisers pay a lot of money for companies to display their ad banner on their site.
This is how companies like Yahoo make money. Each of the pay to surf companies will have you download an adbar. This is a small ad banner that displays these ads that runs on the bottom of your screen while you surf. When the get paid to surf companies accumulate all this money at the end of the month, they keep some for themselves and the rest they give out to it's users. This is where referrals come in.