Other than widgets, I think that tags are the best feature of Wordpress 2.3. Up until now I kept adding more and more categories and things were starting to get ridiculous. But now with tags I have a wonderful middle path. Categories are for broad swaths of posts and there shouldn’t be too many. (Or at least not any more than I currently have) But now, instead of making a new category to talk about Compiz or X11, I can just file it under Linux and add the corresponding tags. Plus, tag clouds are fun!