I found an interesting post recently on Matt Cutts’ blog about some of the best Wordpress “related posts” plugins. The one that was ranked as number one was actually the second or third one that I tried when I was searching for myself, YARPP. (Another one I also came across and liked, but didn’t implement, was the WordPress Related Posts plugin, which Matt also listed.)
One of the features I personally found nice about YARPP is the ability to add to/change the HTML tags that the results are displayed in. For users that may know how to add a class or an ID to a tag, but run a high risk of “breaking” a PHP script by altering it, this is a nice feature. Also, the output at the right in the Dashboard was handy to me, as it gave a bit of assurance that the changes were being saved once I clicked “update”. All in all, I’d say this is good plugin from a usability standpoint. I hear good things about it’s actual performance, so I look forward to seeing how it works out.