I'm a nut about organizing stuff just so, and making sure bits of information are connected, interrelated, categorized, and labeled just right. The "categories" I've heretofore been using for this blog were ample for my initial purposes, but as I creep up on 200 posts, have become a less useful way to organize and access the information.
So I'm turning to tagging and tags, a fairly widespread component of many blogs these days. Basically, each post will be assigned a series of tags that help describe it, and they'll be listed on the post page when you view it on my site (currently located in the right-hand column on each full post page). You can then click on a tag to see other posts that share that tag and are, presumably, related. For example, this post will have tags of "[tag]blog[/tag]", "[tag]meta[/tag]", "[tag]website_development[/tag]" and "[tag]blogging[/tag]", and you can click on any of those to see other articles that share those tags.
I've also added a "tag cloud" to the navigation bar on the front page of my weblog, which shows the most often-used tags. A similar display is now present on the front page of my site. Soon, I will also add an index of sorts that identifies some themes in my writing, composed of groups of related tags. Eventually, I hope to fade out the use of the traditional category system.
Let me know if you find this useful, confusing, or something else entirely.