It is very late and a little mystery is drifting through my brain and I have often wondered about this.
Let's say you answer a question, you hit post, your writing gets "out there" where the whole world can read it. As you reread your post you spot a stupid or embarrassing error. When you hit "edit" to correct your mistake in your original answer is still "out there" or is it invisible until you hit done (update?) for your edit?