How is it possible that "I" (the user Krumelur) exists twice?
33449
Why does Stack Overflow allow duplicate display names?
6948
How to prevent a user from having multiple instances of the Same Web application
86885
Why do some users have username "user########"?
75209
Why is `make_unique` disallowed?
127414
How was this new user able to post two questions less than 40 minutes apart?
45300
How to prevent duplicate usernames when people register?
10353
Duplicate flag lists "you have already raised this flag" after flagging as "Unclear what you're asking"
112077
How to check if a value already exists to avoid duplicates?
68470
Someone is duplicating/reproducing my site what can I do?
100363
How is a variable at the same address producing 2 different values?
40958
Question appears multiple times in a search result with Q : and A :
113181
Customize the Duplicate Username error message in a Community
22831
Changes to "close as duplicate" (part deux)
39619
Infinite keyword duplication
38992
Is the duplicate answer flags raised for exact copies of answers of different users?
140127
Node Access User Reference module tries to grant access twice, creates integrity violation
29772
How is uniq not unique enough that there is also uniq --unique?