(I know that this is actually an extremely bad protocol feature, but this use of it is Something.)

(I know that this is actually an extremely bad protocol feature, but this use of it is Something.)
I mean you absolutely can do it on Mastodon, you just need to own your instance. There was a post backdated to several thousand BC that crashed a bunch of apps a few months back
tangentially related but one of my favorite bits of activitypub shenanigans is when someone put up an instance on a URL consisting of the entire first line of the markiplier five nights at freddy's let's play
yeah, the activitypub connector that poots my indieweb site onto fediverse is more than happy to backdate posts to whenever my feed says theyβre from, and they still appear as brand-new even when itβs having a normal one and backfilling posts I made 20+ years ago.
I actually had to check the timestamp on your comment to verify whether you did or not.
I guess the punchline would sorta be lost if it just said "21 years ago", butβ