What would you expect to find on Google if you searched for "xxx trailers"? Not links to a Van Diesel film from 2002 I'll bet!
Me neither. But that's what you'll get.
And in the absence of any porn content in the serps (until one single entry on page 2) how come Google lists porno adwords ads?
This would seem to be at least partly explained by the views expressed here
http://www.webworkshop.net/seoforum/...ic.php?t=18817
(as referenced by
http://www.greenguysboard.com/board/...ghlight=google)