Originally Posted by u-Bob

by that logic every designer, hosting company, content producer etc would be a scammer as well.

Google is selling traffic. They could spend a lot of time signing up for every affiliate program out there and then show ads with their own affiliate ref codes instead of selling the traffic, right? why aren't they doing this? Because their traffic is crap? Or because they prefer to focus on something else?

Every action has an opportunity cost. People tend to focus on doing what they are best at. Designers sell designs instead of building their own network of sites, not because their designs suck, but because they are better at deigning sites than running sites. Some people sell traffic or part of their traffic because they prefer to build new sites, write new blogposts, optimize their sites,... instead of constantly evaluating new affiliate programs.