Moderation after the fact requires more effort than moderation up front.  Each forum on DotNetNuke has different levels of participation so a post made to a slow forum will take longer to be moderated than a post on an active forum.  What ends up happening is that posts end up in forums where they don't belong, innappropriate posts are very likely to slip through the system and in general chaos ensues.  You only need to go to the free for all forums on ASP.Net to see what happens with no moderation.  The solution that some sites utilize to combat this is to use general community moderation where people report abuse and then a smaller group of moderators actually moderate the abusive posts.  However, what ends up happening is that moderation is much more inconsistent, and often by the time offending posts are flagged, a thread or conversation has already begun requiring moderators to decide whether to edit existing content out or delete an entire thread.  In a moderated forum, this occurs less frequently, and if an unmoderated user does continue to abuse the rules, they can be moved back to moderated status.

I was in the middle of a quote and accidentally hit the update button.