Joshua Achiam urges backing up parts of the internet before bitrot spreads

Joshua Achiam, on X (@jachiam0), says now is probably the time to back up the parts of the internet he wants to keep, because bitrot is coming at a scale he calls beyond comprehension.

He gives no figures in the post.

A reply from @sporadica asks whether Achiam's math implies a third of the internet is already lost. The source for that figure is the reply, not Achiam, and the post does not confirm or deny it.