Today I stumbled across the CommentLuv Plugin and I love it. It is my way of saying thanks for all of your comments: all users that add their blog address will have a link to their last blog entries added at the bottom of their comment. Or as the plugins author puts it:

Comments are a wonderful thing to receive on your blog, adding the dofollow plugin is one way to reward but why not place a link to their last post under their comment, with CommentLuv, you can do that automatically! This is an excellent way to promote comments from your readers.

it’s a really good addition to every blog and I hope it makes an impact on the comments ^^

BTW: sadly only new comments are counted, so people comment, comment, comment