I've enabled categories/tagging for the site, and have in fact made such tagging mandatory. You should assign all future posts to a category -- such as "site information," the category of this post -- by typing a keyword into the "categories" input field. (You can input multiple such tags, by separating them with commas.) If there's already a tag available that's close to what you're typing in, the software will attempt to auto-complete it.

The important part of tagging is that it enables us to think about how posts relate to one another, and to read the site from multiple perspectives -- so if, for instance, you wanted to read what everyone had to say about Barthes, you could click on the "Barthes" tag. There's now also a tag-cloud at left that reveals what we're blogging about most (bigger typeface = more posts).