I am connected to a Google Analytics account that has way more than 5m pageviews /mo and is veeery adult - all goes fine. Only reports are really slow.
Actually, Google LOVES AdSense on adults sites... but you have to make them a ton of money for them to let you do it: http://smackdown.blogsblogsblogs.com/2007/05/26/googles-new-consextual-advertising-program/ Like, this one is nothing but high paying AdSense ads: hairy-sex-videos-porn-dvds.com, does it get more adult than that? -Michael