I recently added something a little fun to the site: a way to view all comments by a particular person.
I've wanted to do this for awhile because I think it's a great way to get a sense of the vibe and history someone might have on a particular site (in this case, mine). Does someone tend to always be crabby or have they generally been pretty good?
On any of the comments on the site, just click on the "All Comments" link. When viewing all comments for a person, you can click on the article title to view the comment in its original location.
Along with this I also added the five most recent comments to the home page.
Fun stuff like this is easy with CakePHP. This took me all of a half hour to integrate. About 4 lines of code in the controller and about 10 lines of code in the view (90% of which is just HTML).