Hello. I am a researcher who studies knowledge management and social media, including group interactions on web message boards. I also run a group blog (currently, on Wordpress) and am investigating switching it over to forum software.
Overall, I'm happy with the group blog except for one major issue--how hard it is for new users to sign up as authors (not just commenters). That would be the major advantage of a web message board.
We're still trying to decide if it would be worth the hassle of a major transition (and the additional cost). If we do switch, I'm interested in something like vBSEO because I believe in the power of name-not-number URLs for SEO.