A simple visual indicator of the age of a post such as a zombie emoji (or something less tacky) is all that is needed to quickly disregard zombie posts you aren't interested in. Forums are great but we definitely need a UX overhaul incorporating the last 15 years of web UX research.
About UX, I agree insofar as web forums have worse usability than Usenet clients had before. However, I don’t see how web UX has improved in the last 15 years, in particular on the desktop, and in particular regarding forum and messaging apps.
