Webfaction, and probably other hosting providers, using a different host and authentication for SMTP. There's a post about it on the Webfaction forums.
Because of this you'll get an error when you create a new user (the user is created but the activation email isn't sent).
I fixed this by modifying /application/controllers/User_controller.php thusly:
In sendActivationEmail before '$mail = new Zend_Mail();' add
$smtpAuth = array('auth' => 'login', 'username' => '[your mailbox name]', 'password' => '[your mailbox password]'); $transport = new Zend_Mail_Transport_Smtp('smtp.webfaction.com', $smtpAuth);
The next question is how to send the forgotten password emails. forgotPasswordAction doesn't seem to use Zend_Mail for some reason and doesn't complain about errors, but neither does it send the email.
Is there any reason why this can't be changed to use Zend_Mail (and thereby authentication)?