See https://astralcodexten.substack.com/p/mostly-skeptical-thoughts-on-the. Ambiguous cases will be determined by Scott Alexander's judgement. Blogs that Scott Alexander is unsure about won't be counted either way.
Related markets:
A consideration: It's difficult to imagine substack being happy with "a majority of the top blogs are clearly written by bots". This market isn't just about what blogs are actually written by bots, but what blogs are knowably written by bots. The former number is determined mainly by technology, the latter mainly by human nature.
(And now for a bit of outgroup-bashing... if there's any class of people who will zealously protect their ground, and have the ability to do it, it's the professional pundits.)
@TomShlomi Let's say January 1. If I forget to do it on exactly that day, I'll use the rankings as of 1/1 if available; otherwise I'll use the earliest rankings available.