HN has edits, in conversation and flow, and it does break sometimes, but in general it's a good.
Discussion forums have had edits forever; reddit famously lets you go and delete all your existing posts at anytime by replacing them with "edited by autodeleter9000".
Discussion forums have had edits forever; reddit famously lets you go and delete all your existing posts at anytime by replacing them with "edited by autodeleter9000".