Would it be fair comment to say that if your site runs affiliate links then its at a disadvantage in the organic results? I am drawing attention to this because I have some pretty clear cut evidence that one of our websites was just blacklisted in adwords because it contains affiliate links. If Google considers these sites as such low quality in the paid results then its not a big assumption that sooner or later they will figure out a way to slap the organic results with the same rule. In my case it was manual, the mountain view IP turned up on my stats, followed one exit link, returned to the site for one page view and within minutes I had the nasty email in front of me. And just to be clear my site has been running this way since 2003 using adwords and has in excess of 40,000 registered members. I can see quite a few sites running in the same space that are much thinner than ours!