when a user tries to register, a field goes red if there is something unacceptable. Sometimes this is that the user has already registered with that email address, or that someone else might have chosen the same username. We need a message that comes up explaining the problem, rather than leaving users to guess.
Some users, quite reasonably, have forgotten their usernames. We need to add a link (similar to “lost password”) called “lost username”, which will simply request your email address, check with username is registered to it, and email your the username. If a user is *really* lost, at least they could then also request a new password without having to wait for an administrator to do anything manually.