Jerry that happened to me on my first week as a member of the forum.
Some troll had replied to a thread that was a year old, It was on the top of the "today's posts" list, I replied to the most recent post, then a little later on the first poster DELETED the post I replied to.
(I learned real quick that the quote button is my friend.)
That little maneuver gleaned me a few "don't bring up old posts" replies.
There should also be a small window to retract a post, then after a few minutes, it becomes etched in stone.
VB allows the owner to set time limits on deleting and editing.
Yeah I know some people update posts well after they made them, but that gets confusing, since I already read the original post, I seldom go back and read the same post twice.
Also allowing an infinite time limit on edits give opportunity to someone to change text after they make a fool of themselves by posting something shameful, rude, shocking or lame.