In certain cases, not all participants of an event have their own e-mail address or this e-mail address does exist, but is not intended for use in third-party applications. With the assignment of user names this problem can now be avoided.
Of course it's also possible to define an e-mail address as user name. To enable this without restrictions, the special characters "-","_","." and "@" are permissible.
A given username is not edited by the user, but can only be changed by a CMS administrator. If the user creates a username during registration, the user will receive a hint and an alternative suggestion if the desired username is already assigned.
Further information on (re-)assigning and importing user names can be found in our whitepaper.