The only thing I ever edited after a long while was to take my photo off the photo thread....suddenly had a paranoia attack and decided to remove it...
Each time I edit, I say why I have done so. Edit for spelling, etc. I've often wondered about complete posts that disappear. A few people come to mind. I flipped through a thread today and DCL was GONE. WTF? DCL? A tease, a nothing, what was that about? Though he did generate a whole bunch of questions about what was posted and poof, was gone.
The only time I edit my posts is when I want to correct a spelling or grammar mistake. I like to include trimmed quotes that are relevant to what I am discussing even though the original post is still there - it keeps the context, especially if the BB system puts my post out of order, someone sneaks a post in while I am replying, or someone edits their post and denies what they actually said. I have not seen that here, but when I was on Compuserve years ago it was a very common thing for some people to do.