In looking back at this thread a couple of points pop into mind. Perhaps the title should have eluded to the historical aspect of how SEO has tainted the business because my grip, to some degree is how, over time, the SEO game has caused the Search Engines to respond (leading us to where we are now i.e. the edge of uncharted territory, wondering what to do next).
Gaming the system is as old as the human race and I've no illusions about that changing any time soon. So too, I have no doubt, that those being gamed will continue to respond in kind. I'm convinced (for me) that focusing on the quality of my product is the responsible way to go. Again, if yourprimary goal as a webmaster is to make money, there will always be the urge to try and "manipulate" the outcome to your advantage. It's basic human nature and a fact of business. I just don't think continuing down this path will be good for the Internet and may not even be in your own best interests either (long-term).
We can thank the #*$! industry for pioneering many of the techniques used in marketing today (popups, pop-unders, link farms, etc. ad nauseam) but it doesn't mean there's not a better way, a more responsible way.
There were a couple more points I wanted to make but football is starting so will have to pick this up later. I'm guessing it's gonna be a slow Adsense day today.