We have many explicit PR reps on NeoGAF, so there's no issue. The rules are strict and straightforward: no self-promotional threads, no artificial bumping, no pasting PR materials. PR folks can participate by answering questions, clarifying positions, or by participating as normal, all in their own words. It's mutually beneficial but does not color the discussion, and anything said by a PR rep is taken with an appropriate bag of salt. "He lied to us!!!! Evil mean person!!" is not a position that makes any sense if you apply an iota of sense and critical thought to what a PR rep's job is.