MT-Moderate provides additional functionality for your Movable Type-powered site, which enhances the feedback by enabling additional control over how the feedback is processed. Notably options are provided where both comments and trackbacks can be either moderated or junked based on the age of the entry or the age of the most recent comment received on the entry.
The reason for this is that most recent entries on a site are generally the busiest as far as valid feedback goes, while older entries are the most likely targets for spam, so using this enhanced configuration should cut down on the manual processing of feedback for any site administrator.
Processing options can be made at the site level and individual changes can be made on individual blogs as well, so if you would like to implement different settings for different areas of your installation, that is completely possible.
As one of the oldest spam utilities for Movable Type - and in fact the plugin that is responsible for introducing moderation to trackbacks before it was added to the core system - MT-Moderate should be a part of your spam-fighting arsenal.
Movable Type versions: 4.3