Content moderation
This note just talks about available modules to do content moderation, NOT about the desirability of doing so.
There are several modules (competing) in Drupal that allow one to restrict certain people from posting directly to the live site. Their changes have to be approved by a moderator before they become live.
We currently have one mild form of that on the site. All new content is examined for being SPAM. If it passes it is posted. If mollom is unsure if it is spam the submitter has to enter a CAPTCHA so that automatic submissions are blocked. Definite spam is blocked. Certain roles (editor, admin) are exempt from the checks.
We also have several moderators on the Forum pages (and some comments). They all do ex post facto moderation. The posts happen but they moderators may delete them. Such deletions have been very rare and mostly well disguised spam.
Here are the existing Drupal modules:
These all work on both D5 and D6 and none have any progress toward which will win on D7.