They're not scams, just a faulty or harassed business model that has a short lifespan, like a biz built around the 2010 Olympics. By faulty I mean the paid surfs were/are just an ad coop that used language implying they were an 'investment security' (135% returns and what not). This mistake in hype naturally invited a backlash. By harassed, I mean a few years ago they came under heavy fire by the government and media, because they jumped on the "investment security" buzztalk and slammed them as 'Ponzis.' It was a false charge (as having a pyramid structure doesn't prove intent to defraud), but the media picked up on this to spread bad will about paid surfing.
Both the main programs and their supporting payment processors were then repeatedly disrupted or had their operations halted via freezing assets, or even through government backed DDOS attacks on the websites. The best programs closed down under this assault, causing their sabotaging opponents to cry, "see, they can't pay out." The result was the momentum of the community was stopped, and to this day almost no surf program gains enough members to be successful like in the 12DailyPro years of yore.
You can look for free surfs that pay out, but the paid ones were and are the only ones that make the surfing involved worthwhile. These days, I say just go select some autosurfs that have been around for a few months, ones that use Liberty Reserve (the best processor left standing, and offshore). Put in some initial money, surf til the amount doubles after 1-2 cycles, repocket your original amount and use the extra as 'free ride' money with that surf. Review threads on talkgold or MMG to guide your selection process. Hope this helps.