I'd like to throw in my support for this idea.
I looked at OpenACS in the pre- and early 4.5 days last year and found its polish lacking. It's getting better, and bboards have gotten immensely better functionally, but it's time to take the last step and become slickified :)
First my outlook:
-phpBB is clearly the most visible, 'winning' open bulletin board system. Ergo, OpenACS immediately and automatically stands to learn from it--simply by virtue of 'what is phpBB doing to be so widely used?'
-Besides the continued dependence on aolserver (which I'm not against--let me finish the point), I believe that OpenACS needs strongly to fix social 'bugs' preventing uptake. The toolkit needs to have a strong out of the box experience, and bboards is arguably the most important experience that stands between now and wider use.
Private Messaging: increases stickyness of the site, as Vadim alluded to. Include it as an option--let's not let this be something easy to implement that will be counted as a drawback by users and socially-aware implementers
Streamlined Admin: this cannot be overemphasized, e.g. in response to Jon and Vadim. Although we may know that OpenACS is a toolkit with all these cool sub-site and general admin features, out of box is paramount. It must be dirt-simple to set up a bboard and--dare I say it--delegate bboard admining to a pool of admins and give them an experience similar to the most successful phpBB sites. Whether this OOB experience is implemented as a careful rewrite of overall admin or as a special package-specific extension, the end experience has to be streamlined.
What I think is so striking about phpBB is how impressively well stitched its UI is... not to denigrate anyone here, but phpBB leaves an indelible impression with its default and many of its other skins (another great example close to home: http://forums.gentoo.org ). I don't have a quick answer to this either except that we need to continue to refine the look. I can predict that the ruling text-oriented camp may need to be supplemented with a camp of people dedicated to making the UI (or one skin/version of it) as polished and graphics-inclusive as phpBB is (an objection I fully expect to gather from many oacs regulars).
Oh yeah, lastly: fun there is a 'serious' quality about oacs; there is a 'fun' quality about many bboards, esp. phpBB ones, and esp. ones with some level of Avatar customization capability. This is a must-have (if optional) feature IMO.
I am of course volunteering to help Lars and whomever in this endeavor... still getting my dev env setup... dang interruptions...
