Can one have any (nonduplicate) username?

What if one chooses username "jewhunter"?

There may be other names which are rather political or opinion, who decides on this?

• Actually, people can have duplicate usernames, perhaps confusingly. The moderators of the site and/or the people who run SE have sometimes changed usernames in the past. – davidlowryduda Jun 25 '14 at 17:21
• I would find any name which has almost purely racist/sexist/offensive meaning to be offensive. I am also not a fan of using names of actual people when it's clear you're not them (e.g. Bill Clinton) and that includes "slight typos" in that matter. – Asaf Karagila Jun 25 '14 at 17:22
• – Asaf Karagila Jun 25 '14 at 17:24
• But how do I know you're really the Asaf Karagila...$${}{}$$>.>$${}{}$$<.< – Emily Jun 25 '14 at 18:00
• @Arkamis: You ask Arthur Fischer, Michael Greinecker, Gerry Myerson, amongst others. – Asaf Karagila Jun 25 '14 at 18:19
• @AsafKaragila Maybe someone else was using your account in between.. – emcor Jun 25 '14 at 18:22
• emcor, unlikely. I'm almost constantly online. – Asaf Karagila Jun 25 '14 at 18:24
• See more here: meta.math.stackexchange.com/a/8884/442 – GEdgar Jun 27 '14 at 14:19

There are very few rules on user names, duplicates are explicitly allowed. But there are some restrictions:

• Impersonation of other users is not allowed (having the same name is not necessarily impersonation)
• The diamond symbol indicating a moderator can't be used in user names
• Offensive user names will be forcibly changed by moderators. The decision on whether a user name is offensive is made on a case-by-case basis by the moderators.
• I expect it can be a difficult call, sometimes. Ages ago I met a female Iranian mathematician whose first name was Nazi. That might not work really well as a user name, though it is apparently a perfectly fine Persian name. – Harald Hanche-Olsen Jun 27 '14 at 14:20
• @Haran: According to a quick Wikipedia check there at at least two places in Iran called Nazi too. – Asaf Karagila Jun 29 '14 at 8:23
• What if a moderator has the name of another user? Does that mean the other user can't use their name? I would vehemently disagree with not allowing someone to use their name because some moderator shares the same name them. – dustin Mar 9 '15 at 17:53
• @dustin Unless you're doing anything else to imply that you're a moderator or intentionally try to cause confusion, just having the same username as a moderator is no problem at all. – Mad Scientist Mar 9 '15 at 18:00