Dear Author analyzes the category metadata of what got deranked.
Making Light suggests one way this could have happened --kind of a cross between the telephone game gone wrong and the possible use of a pre-made list of "offensive" materials from a net nanny or similar.</a>
More thoughts from sbisson on the gradual process of such a massive screw-up, and the reasons why Amazon can't just hit a button and fix it
While different folks have different theories on what exactly happened, and why, everybody seems to agree that Amazon execs and programmers are going to be having a Terrible, Horrible, No Good Very Bad Day. I, personally, am leaning more in favor of Corporate Stupid than Evil Intent, frankly, because the level of clueless stupid seems too high for the latter-- and also because I can see where an originally good idea about restricting the chances that _actual_ pornographic materials would come up in innocuous searches could mutate horribly as it got passed through different levels of a very large corporate hierarchy and into attempts to program something like that.