That's right. Today I found someone doing a simple thing and he is making tens of thousands of dollars daily from google. How he does it? Make domains (with poor, random content full with keywords but they look like articles) and each domain has been limited to few thousands. He probably has thousands of domains under his name. Make the pages rank on google (most of his pages are on page 1) through different domains and therefore taking the whole page. The page is article for google but it is an adpage for visitor (using some detection script) so each visitor is like a click on ad. He is ending up with hundreds of thousands of clicks daily from google! example of domain - asc.epf.uni-mb.si
The amount of time spent on doing this should of been invested in one site -- would of been the same (or better). -Epage