This is a great rule. I follow it in all my talks and in all my blog posts, as well. Meta talk is, frankly, rather boring and distracts from the primary focus of the talk/post. I find that when you intentionally attempt to steer away from being self-referential your writing becomes much more lucid and to the point. You're no longer dwelling on the process but driving home a singular point.

I do have one corollary, though: Anecdotes work great for talks and blog posts. Instead of talking about "when I was writing this post/presentation" talk about "there was this one time when this user did X" or "when I was working on this team Y happened." They're almost universally a crowd pleaser.