>>63866
Threads exist as static HTML pages (unless you're viewing as a mod or using the live frontend I believe), and they don't get refreshed until something triggers it, such as a new post or something else. This saves us from unnecessary processing on the server every time someone opens a thread

>>63868
This is a different website to 4chan after all - plus there was no such hover message on 4chan until relatively recent times

Behold what happens when you click a post number on Futaba: https://may.2chan.net/b/