After looking at a couple of WordPress plugins that implement Techorati tagging, I decided to go with Ben O'Neil's Technorati Tags plugin. I did not like some of the default settings, so I made some modifications, the most notable of which was adding a link to the Technorati Tags help page before the tags' listing. Since I only had one post on the blog where I had actually explicitly defined tags, the empty "tags:" on the majority of the posts seemed a bit ugly to me.
Looking at the plugin's code, I noticed that it seemed to contain code to prevent this, but it was not working properly (the $tagArray variable, which is supposed to contain the post's tags, was never 0, but always 1). To fix this, I changed line 214 from
if (count($tagArray) == 0)
if ((count($tagArray) == 1) && ($tagArray == ''))This should still work if a post happens to contain one tag.