Hiya!
"Other". We all talk about it, we go over what caused it...and yeah, as DM I will give out some pertinent info at this point about pre-made NPC/Monster plans, things they missed that lead to their downfall, and some "behind the scenes" things, but still keep the "big stuff" a secret.
Then everyone makes new characters and we choose a starting location for them. Sometimes it's in a completely different part of the campaign world, but usually it's "in the area". For example, if the TPK happens in a ruined keep a few kilometers outside of the Town of Threshold, we may start on a different road, just coming into Threshold.
What "happened" still happened. We don't "start anew" or otherwise wipe the slate clean and do a complete reboot. We aren't playing a video game... we are playing in a table-top campaign setting, with a history and timeline and all that. If the TPK happened on "Day 19", I might have the PC's arrive at Threshold on "Day 22". They go to the one and only good 'adventurers inn', and after a light meal the bar maid might ask "So, you adventurers part of those other guys who came by a few days ago? Headed out to the Old Keep an hour or so down the West Road?" or something like that.
Then the Players decide; they take it and go to the keep, or they say "Nope. Not us. We're new here" and so on.
EDIT: At least it's a GOOD Necrothread!
^_^
Paul L. Ming