TOPIC: REGISTRATION VARIABLES

What is meant with this:

You can pull in variables from your registration by using this format (without the brackets):

User Data: $user->[fieldname]
Event Data: $user->event->[fieldname]

i thought i would be able to have the variables from the registration done before used in this script but:

when using a mailscript and pass for example "$user->email" by $m_email = $user->email; or even direct in the message message text, nothing happens.