Account creation user experience/Usernames

This subpage of Account creation UX is to describe how usernames are dealt with by the English Wikipedia account creation process.

Current
Usernames must comply with the technical limitations set out in...


 * 1)
 * 2) Extension:AntiSpoof
 * Title blacklist and MediaWiki:Titleblacklist (because usernames are also page titles)

These entail that...


 * It may not already exist, of course, including in SUL.
 * It may not be more than 235 characters long. See
 * It may not be an IP address.
 * It may not be one of a list of configured reserved usernames. See
 * It may not have a namespace or interwiki prefix, e.g. User:Wikipedia:Jimmy Wales
 * It may not contain '#' or '/'.
 * It may not contain various control characters, unusual whitespace, or UTF-8 private use characters: U+0080–U+009F, U+00A0, U+2000–U+200F, U+2028–U+202F, U+3000, or U+E000–U+F8FF.
 * It may not contain '@'.

There are additionally policies set by the community which govern what kind of usernames are unacceptable. These choices, such as putting 'bot' or 'sysop' in your username, may result in an indefinite block for the account.

Future
In addition to the requirements listed above, we should test using heuristics derived from community policy. Checking for problems before a user registers will reduce the number of those who must be blocked post-signup for usernames which are inappropriate. Eligible candidates for adding to the username checks include...