The shopping comparison sites I think are fraught with bait-and-switch logic at rates much higher than those shown above. They send an XML feed to the comparo engine fully intending to redirect shoppers to alternative products. I have seen it myself at least 4-5 times while shopping for the holidays.

Which may have had an effect of making the overall database more safe.

One can assume a correlatation between Black hat SEO and spam sites.

Also, since many of the Search Engines appear to be demoting sites that have not attained a certain Trust Rank or Quality Backlinks, this may also be a factor

Perhaps users or competitors also complained about sites in the TOP 30 they chose to ‘out’ for bad techniques. Search Engines have been inviting replies in their SERPs.

But since AOL is using Google’s SERPs, it is odd that there would be that degree of differences between their rankings.

Ask uses ‘Expert Rank’ – so perhaps there is a possiblity that even valuable sites may have to resort to questionable tactics to remain free and competative.