[I, Brian]

I just thought I'd point out that in the SEO community the use of nofollow has been suggested as a way to devalue pages.

The purpose of a nofollow tag is not simply indicate a link should be ignored, but also that the page content is subject to third party interference.

Therefore if people think that implementing this hack could be a great way to "horde PageRank" or other such strategy, then they may find what they actually achieve is simply a way of telling search engines that the forum itself is nothing but a collection of "free for all" pages and should be devalued.

Webmasters should consider very carefully why they wish to use nofollow, because if it's for SEO purposes then there is a real possibility that the plan could backfire on you.