On our system, many people subscribe to get digests daily or every few days. The template for digests looks odd in this case, with “Popular topics” at the top. Digests for discourse sites used for blog discussions also have this effect, like this example from @codinghorror blog received today. It seems to me that if there’s only one post (or even 5), it shouldn’t have a heading with “Popular Posts”.
edit: compare this to WordPress.com notifications - just got one this morning from my wife’s blog. Frankly, I like the WordPress.com notification better, since it is more clearly just a notification about a new post.
Note to self: a more general question that I need to dig into is to what extent it’s even possible to edit these templates.