On 04/30/2016 12:22 PM, Gordon Messmer wrote: > On 04/30/2016 11:28 AM, Alice Wonder wrote: >> Is there any advice on characters to allow in usernames? > ... >> I don't think a whitelist alphabet is best approach because of people >> with names that are not spelled with Latin characters. >> >> Is there an existing blacklist of characters that technically legal >> but are generally avoided in e-mail addresses? > > The RFC uses a list of allowed characters, and so must you. For e-mail sent to people, yes. But for what usernames are allowed when creating an account, I don't see why blacklisting characters that are not allowed in a username is a standards problem.