All those who wanted to monetize their web sites had a big boost a couple of years ago when Google rolled out their AdSense program. I jumped on board, just like I jumped on the new upstart named "Amazon" when they first appeared on the scene. Amazon has cut its affiliates commissions back to near-oblivion, in the interest of their profits -- why did we think Google wouldn't do the same?
But, as it goes on the web, most players weren't content with running an honest web site with honest content. I've complained and complained to deft ears about how so many sites are 'cheating' by stacking their links and all manner of other tricks to increase their clicks. Google finally caught on.