Inspired by a similar question on meta.stackoverflow, I just did this database query on superuser, and found 103 pairs of questions with totally identical title, excluding those where one of them is already closed. (There are some merged questions in the list, if those were not closed before merging.)
- In some cases these might be simple duplicates, then vote to close. (If you think the to-be-closed one has valuable answers, you might flag it for moderator attention, so it can be merged.)
- In other cases one or both questions might have a bad title, then edit the title (and maybe the text and tags, if you are on it) to make them better (and distinct).
mod note: to prevent excessive flags, please use the following guidelines for how to handle these types of questions:
- If they are (mostly) exact duplicates, exercise your vote-to-close privileges if you have over 3k
- Whether or not you have reached 3k, post in the vote-to-close chat room
If the questions are exact duplicates by the same user (i.e. they posted the same thing twice), then flag them for a moderator, and in the message, tell us that they need merging because the same user posted twice
If the questions have some differences and both have quality answers, then do some editing to differentiate them a bit. You don't necessarily need to vote to close.
Once a duplicate is closed, if they are 100% identical, then you can flag them and ask for them to be merged. Flag the closed post and request in the mod message box that it be merged into the duplicate. Only do this if they really are so identical that you can't tell the difference, and the answers on one would make 100% sense on the other.
If a duplicate is of very low quality, and has low views, you can vote to delete it (or post in the vote to close/delete room if you don't have 10k). You can also create a meta post requesting that a list of questions be burninated or merged, and moderators and 10k+ users can work through the list as they have time.