If you delete a comment, should you leave a new comment to explain it? If there are already other comments referencing it, I usually see something like "I've deleted my earlier comment that @whoever was referring to" for clarity. That seems like a good idea to me.
But what if the deleted comment is the only one for a given question/answer, or it isn't commented on by another person? I've seen that go both ways, and I'm not sure which way is better. When I've done it, I've just let them disappear, but I can see how some people might find it annoying to search many posts for an old comment that they can never find.
So, is there a rule on this? If yes, what; if no, come up with one, I suppose.
EDIT: As Bill the Lizard pointed out, yes, I'm talking about people deleting their own comments. I did briefly think about the case of other people making edits, but I don't have any experience with that due to insufficient rep so I dropped it.
EDIT AGAIN: Seems like there is no correct answer, so I'm CWing this question. Even though it seems like nobody else will bother posting an answer anyways.