In general, if I was responsible for a forum, and one in which it was important for me to spend the time, I would dedicate a some time each day to gardening. For example, that posting from onecore.net that mahesh2k posted, I would delete the body of the post and replace it with a link to a specific paragraph in a policy document (or FAQ) that states why the post was removed. Eventually trusted moderators can take over. I would also add [Editor's Note:] to postings with links to relevant guidance. For example, something like, "When including source code in your posting use the [code][/code] tags for better formatting." and include a link to a how-to document showing a beginner, intermediate, and advanced examples of using the [code] tag.
I think that the number one reason discussion groups, of any form, are useful, is because they provide a filtered/vetted/focused discussion of the topic. Anything that worsens the signal to noise ratio will eventually kill the discussion group.[/code]