"Most people who use forum systems such as vBulletin or PHPBB are used to having lots of extra features that Drupal core's forums don't contain by default, including private messages, smilies, and BBcode. While all of those are available as contributed modules, there are two "must-have" forum features that are a bit trickier, since they deal with access control: private forums, and forum moderators.

Drupal core tends to have an "all or nothing" approach to these issues. Either a particular role can access all content on the site, or they can access none of it. Either a particular role can administer all forums, or they can administer none of them. Luckily, though, Drupal provides a number of hooks so that contributed modules can add in their own robust access handling."

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