FourDegreez - 5:04 pm on May 21, 2010 (gmt 0)
Option A would create a lot of empty shell pages, which Google doesn't like. I think if you were to go this route, you'd have to expose a paragraph or two of teaser content. But your users might not like that if the forum is meant to be private.
What I did was allow the user the option of making a post public. Posts are private by default.