Ajax Rating is a plugin for Movable Type that enables visitors to rate your entries or your blog.
The "Pro" version of Ajax Rating lets you rate comments, trackbacks, categories, authors, tags, and just about anything else. Added features include threshold viewing for comments based on rating, listing "hot" items, and comment reporting.
You can see Ajax Rating Pro in action in this plugin directory, as it is used to power the ratings for each plugin.
Movable Type versions: 4.3