Validation on username? Just wondering if theres anyway to force some validation on the username?
I have usernames being displayed locally, and therefore I'm trying to prevent email addresses being used. I have my client side validation set up with regex to prevent an email being used, but some users still seem to have been able to register with the email as there username (presumably they have JS disabled). 

It would be nice to enforce that validation server side.
I don't know if there is anything natively in Craft to do this, but you could achieve it quite easily with a single file plugin:

public function init()
{
    craft()-&gt;on('users.onBeforeSaveUser', function(Event $event) {
        // Only do anything if it is a front end submission
        if(craft()-&gt;request-&gt;isSiteRequest())
        {
            $username = craft()-&gt;request-&gt;getPost('username', null);
            if($this-&gt;isEmail($username))
            {
                $event-&gt;params['user']-&gt;addErrors(array('username' =&gt; Craft::t('You cannot use an email')));
                $event-&gt;performAction = false;
            }
        }
    });
}