This fits well with the recent discussion about blog spam: apparently there are currently a number of pseudo-blogs that have been set up solely for the purpose of building Google juice and then later being converted into porn sites once many Google results point there. I'm not sure if that's really the clever strategy — Google throws out the corresponding results at the latest after the next Google Dance (the reorganization of Google indices based on newer Google robot results). And a Google Dance happens often enough that you really can't build lasting results that way.
What would be a fairly insidious technique, however, is if the Googlebot continued to be presented with the pseudo-blogs (it's recognizable to the web server by its user agent specification) while only regular user browsers saw the porn sites. That way Google would continue to diligently index a pseudo-blog and direct users to the home page of this pseudo-blog, where they'd then see the smut.