Okay-- Mark (or Dottie, for that matter) can feel free to correct me here, but I'm going to offer an explanation as I'm (elsewhere) a message board administrator myself.
1. Intellectual property issues: who 'owns' the content that an individual user posts on a message board? Is it the board administrator/host? The community of the board? Or the user who made the post?
I can't speak for Davidson's message boards, but in the case of the site I'm an Admin for, it's the individual.
Kind of, anyway. The thing is, we WILL NOT (with a few highly limited and TBD/as-needed situations) eliminate someone's posts in a quote by another member... but we also will NOT prevent a person from gutting a thread by deleting their own posts. Yes, this is deeply unfortunate, and we do try to discourage people from doing this. But ultimately, it
is their intellectual property, as well as a conversation within the community.
2. Sometimes, one's opinion changes, or one's perspective does, or one's need for anonymity/privacy does. When that happens, a member may quietly opt to delete themselves from a public message board by deleting posts.
Aside from reminding members that people reading can-- and often DO!-- benefit from reading even old posts... there really isn't much that can be done about it. Message boards that "hold hostage" the words of members (by not allowing editing past some window) don't tend to be very active because they make people wary of sharing freely.
Our own board has dealt with the community's need to have older threads at least make SOME kind of sense even after member edit/deletions via eliminating the post-delete option for all but our moderators. That way, nothing stops a member from basically reducing a post to:
But at least the entry doesn't vanish from the thread as though it wasn't ever there to begin with, if that makes sense.
