Allow OpenID based commenters to add their thoughts via comments on your WordPress blog. This plugin is not an OpenID server.
Add license terms to your comment form.
Allows you to display a captcha on your comment form to avoid spam.
Restore the comments number after the 2.5 upgrade.
YATCP allows you to have threaded comments (i.e. reply to existing comments) in your wordpress.
This will enable ranking of your posts by popularity using the behavior of your visitors to determine each post's popularity. That Plugin is base
Use avatars from services like Gravatar and MyBlogLog in your posts, comments and pingbacks
Displays the comments in reverse order.
A text filter that will convert your posts and comments to LOLcat-style language.