I found Notion's URL schema interesting as well. They have to contend with renames of pages, reorganisation of the hierarchy and all that. So they have something like: notion.so/:account/Current-Name-of-Page-:pageid where the name changes if the page is renamed, but the redirect works, as the page ID is unchanged. In fact, one can just use notion.so/:account/:pageid and gets redirected to the right page, or even noti…
So, if Paul Graham hosted his site via Notion (he doesn't), I could link someone to `https://paulgraham.com/Why-I-Hate-Hackernews-be2839f0-e145-4...` and it would show my (fake) page on PG's domain.