A bboard would be good, but I think a lot more could be done with such a site (whether its part of the openacs site or not).
Not-for-profits tend to be able to scare up smart folks, at least larger ones like Portland Audubon, but folks on the board and staff tend to be someone unknowledgable of computer technology. The Portland Audubon board has three fine and intellegent biologists on it - one ran the Endangered Species program of the USF&W under Carter, another the USF&W's Region 1 (the PNW), and another all USF&W refuges in California and Nevada. There are also vets, lawyers, accountants etc.
These people could really use some background material on just what kind of stuff a community-oriented web site could bring to the table. A directory of good non-profit sites (not restricted to those implemented by variants of the ACS) would be really useful as it would give folks like this targets to strive towards.
Such a resource could give weight to the claims made by members or fellow staff/board members about just what can be done at reasonable price, by providing ammunition for use on technophobic skeptics.
So I think the aD Foundation has a real chance to build THE prime web-based resource on web technology for non-profits, above and beyond simple issues related to using the ACS to build a web presence.