Thanks! If you're interested in making nested tags for your own journal, I followed a very helpful tutorial by wistfuljane, here.

As far as the headers: *nods*. It's a good question. Mostly I've left it up to the authors' discretion, but if we're getting larger as a community, some guidelines might be called for. I'll see about writing up a mod post on the subject, though I don't think this will be an issue that requires a lot of policing. (Yet--I guess it depends on how popular we become!)