You should drop a note on your blog about the new chapter(s). I'm subscribed to your blog's RSS, but not the one for craftinginterpreters.com—because a feed for the latter doesn't actually exist.
I think I used to do that for my first book, ages ago, but these days it seems like not many people are using RSS. Interestingly enough, I did just start using RSS again myself recently.
Posting on my blog feels kind of heavyweight for this, though. Do you do email? If so, subscribing to the mailing list is a good way to get notified. I only use the list for new chapters and other "major announcement" stuff like that, so it's not spammy.
I didn't mean to suggest you do this for every chapter. Just something in the vein of, "In case you haven't been following along already, since I last blogged, I've completed several chapters of Crafting Interpreters."
