It works like this: hackers exploiting lax FTP security, insert porn material onto a site with a view to stealing bandwidth from their victims. The material is linked to an "adult" site and served up whenever porno punters hit on the graphics. Corporate brochure sites are popular - overspecced and underused, the pornjacker's material can sit happily for months without the host noticing anything amiss.
Please keep comments on topic and to the point. Inappropriate comments may be deleted.
Note that markup is stripped from comments; URLs will be automatically converted into links.