HB wrote:In theory, internal links are considered in the distribution of page rank within a site. For example, a frequently linked article within your site will have higher rank than another article with only one internal link. That said, I would not bother with a recent posts section unless you feel it enhances your membership's enjoyment of the site. The site you mentioned is using it to show a cross-forum view and it does make it appear more "active."

BTW, in a recent demonstration of openness, Google webmaster tools added tabs in their sitemaps interface for showing links from internal and external pages, eliminating any doubt that they track inter-site linking. What they actually do with it SEO-wise, one can only speculate.