Inspired by a similar question on meta.stackoverflow, I just did this database query on math.se, and found 81 pairs of questions with totally identical title. (Ordered pairs where id1 < id2, excluding ones where one or both of the questions is already closed.)
- In some cases these might be simple duplicates, then vote to close.
- In other cases one or both questions might have a bad title, then edit the title (and maybe a part of the question and tags, if you are on it) to make them better (and distinct).
To avoid bumping to many of those questions to the front page (pushing off new questions), you might do this editing once in a while, not all at once.