I finally got around to doing something I've wanted to do for ages, only to discover it could be done in all of fifteen minutes. I'm talking about per-category feeds on jtauber.com
For over a year, my django-atompub has supported the parameterized feeds that django's built-in syndication feeds do but I never made use of them myself.
Fifteen minutes and roughly 20 lines of code later, the site now has a separate feed for each category. If you go to a page that is also a category, such as python or django or music theory or filmmaking or poincare project there will both be an extra feed advertised in the html head and a link from the "feed icon" after the list of "Pages in this category". So if you are only interested in a particular topic you can just subscribe to that (although I hope you don't—I did this more for topical aggregators)
One thing I always struggled with when thinking about category feeds before was how to handle subsumption relationships. If I put something in django should it automatically go in python? If in python then in some broader software category? or computing category? I certainly want to avoid the assumption of hierarchy (see some previous posts on that topic).
So for now I've left categories with no additional structure.