Using variables in intro

Hello!

I'm creating a custom intro for a list, and would like to include some 
variables in the intro, such as e-mail address of the particular 
subscription request. Is this possible? I looked at the source and saw that 
when creating the default intro it uses $subscriber as the placeholder for 
this, but when I used this in my custom intro it is written verbatim.

-- 
Toomas Aas