Back in the day, when porn was in the big online bubble state, sites would offer over $.50/click to their site. When I first started (ab)using that system, the sites immediately bumped it to $.25/click and then $.10/click, and now I think its like $.000034/click, or basically nothing. They would also give you additional money for actual sign ups, and had a bonus day on every month where you made a significant amount more for sign ups.
Ultimately I think I cashed in like $7000 when I was 12 before shit hit the fan and the company my buddy and I were using sent him a check that bounced. It was tough explaining it to our parents, but ultimately everyone knew about alladvantage and we would always say it was something similar to that. We also cashed in on alladvantage, I think it was $20/month just to have the thing on for a few hours.