Having found the cause of web pages loading slowly on my computer, I was frustrated to see some web pages still taking minutes to load. Why? Oh, yes, they are all Wordpress blogs. Wordpress blogs are slow. They take minutes to load if they ever do. It's a well known problem, but even the Wordpress pages about the problem (Why is my Wordpress so slow? Are your sites running slow?) take minutes to load, and they don't even have the answer.
The answer is to block Gravitar images with an AdBlock filter:
*.gravatar.com/avatar/*I'd found a couple of pages correctly identifying the problem, and applied the AdBlock solution previously, but after trying out Fedora and coming back to Debian, I hadn't re-applied the filter.