I personally hate the idea of behavioral advertising on the 'net, mostly because huge corporations will use it to track and catalog our every move, while small companies like mine will struggle to overcome the limitations it puts on us. I also hate that ANYBODY is tracking and classifying me based on my online habits. If I click a particular link and that move serves up a particular ad, fine. But if I come back a month later and you serve ads based on what I've done while away, BAD. That's where it's headed.
Another thing - how can you track your SERPS if they're different for everybody based on previous 'net usage and geo-location? That's why I frequently use
Scroogle Scraper and compare it with my normal search results. This might surprise you!