Looking through old questions I have com across many dead links. There seams to me no real consensus across the SE network as to what should be done with dead links. I have read many questions (1,2,3) about dead links and they say: just leave a comment; or edit the post to update the link. Flagging seams to be discouraged, but there is no definitive answer.
Here on BSE what should we do when we come across a dead link?