Advanced Comment Trigger
Advanced Comment Trigger provides a new trigger category allowing automatic unpublishing of comments based on more fine-grained criteria than the default "new comment added" trigger. Currently, this module can unpublish comments based on the number of hyperlinks in them. It can also exempt this restriction for certain user roles or comments on certain content types. For example, all site admins could be allowed to post comments with hyperlinks without restriction, or all comments on forum topics could be allowed.
Future plans for this module include additional actions, such as emailing the post author or site administrator(s) or blocking the commenter's user account.
Users of this module might also be interested in the included exported View, which can provide an RSS feed of all of a site's moderated comments. To use, install the Views module, go to admin/build/views/import, and paste in the view source. Then view the RSS feed at comments/moderated/feed on your site.