You may have noticed I've added topics to the side column of the site now. I just stuck them there for the moment without concern for aesthetic issues, which I hope to deal with on this site in the next few weeks. I'll also need to re-organize to remove some of the topics that I've ceased to use and merge topics that are redundant.
Back when I was using my fork of Ciaran's Journal tool, I had hacked in topics by replacing another field, but there was never a place that listed all of the topics being used — an article was simply added if I typed in the right name in the box when posting (if I typed in something different, a new topic would be “created”). Now that I can see them all at once, I can see where I've changed topic names at times and can avoid doing likewise in the future.