The furor about this has been building up since the weekend especially on Twitter and Facebook (which is how I came to hear of this first), with the first people to become aware of it being authors who suddenly found themselves stripped of their ratings. (See also Edward Champion's post here.)
Publisher Mark Probst was one of the first to question what was going on. The answer he got from Amazon was evasive :
In consideration of our entire customer base, we exclude "adult" material from appearing in some searches and best seller lists. Since these lists are generated using sales ranks, adult materials must also be excluded from that feature.Novels with hetrosexual sex scenes in them, though, seem to be strangely unaffected! Jackie Collins is still ranked and so is Harold Robbins, although many books in the erotica category have also been stripped of ratings.
More comment today at The Guardian.
A hacker called Weev has claimed credit for creating "the glitch". Amazon is repairing the damage. All our buttons got pushed, hey-ho.
If it's true that this was a case of hacking, why on earth couldn't Amazon have handled public relations more professionally? At the first sniff of a problem, there should have been a notice posted on the site to the effect that they had been notified about the problem and were working to fix it. Now they need to put some serious effort into damage control.
(Wish I could claim credit for the title of this post but nicked it from a wittier friend!)