I have noticed a lot of new "members" at my webmaster-related board (
http://www.fhgstore.com/board/). Lots of people just register there entering a wrong email, so they know for sure they would not be approved to post. I was a little bit curious why they are doing this... When I checked over some suspicious dead (i.e. not-approved) accounts, I've notices they always entered some URL in the "Your Website" field on registration form. But when I checked the list of members there (
http://www.fhgstore.com/board/memberlist.php), I understood the situation... The members.php file is spidered by SE and it has some PR. For instance, my one has PR=2, but I'm sure some more famous boards have much bigger PR on their "members" list. So... all these URLs' (99,9% of them are non-adult at all) are getting spidered and earning some PR from my site. Shit, I had no guess about such a trick earlier. Course I have removed all the URLs' on such fraudulent accounts or replaced them with my own ones. Ok, let's these bastards get that they deserved for.
To summarize all the above, I would recommend all board masters to re-check their members lists for non-approved accounts with false email addresses but working URLs' (as I said above, most of them will be not related to the adult business at all!)
Hope my post will be usefull at least for someone here...