I'm imagining projects will accumulate quite a few discussions. Some will warrant continued attention and thus visibility. However, many discussions will be resolved and should remain as part of the scientific record and as a resource, but do not require the same prominence in the discussion page.
Perhaps an archive feature. It's unclear to me whose decision it should be to archive (perhaps the initial poster) and whether this feature will be needed. An alternative would be a star feature, so extremely pertinent discussions will have enhanced visibility. With starring you could imagine a consensus algorithm determining the degree of sparkle (corresponding to the crowd's decision on the importance of the issues within).
I completely agree that a feature as you describe will be needed and will be very valuable.
An alternative to an archive/star feature would be to have a scale of Importance/Visibility/Attention. Perhaps we'd have 4 buttons:
Very high visibility
Something like that. I would think that for the most part the project leaders could determine the importance of each thread. On the other hand it might be nice to be able to have the community weigh in on what they think is important.
@dhimmel do you feel like this feature would be valuable right away? Right now I'm thinking to wait until there is more activity on the site.
If anyone has additional thoughts on such a feature let us know.