Yes that's possible. You need to use the onBeforeEmailUser trigger with the AcyMailing action. The variables available to onBeforeEmailUser are as follows.
Code:
$_PLUGINS->trigger( 'onBeforeEmailUser', array( &$rowFrom, &$rowTo, 1, &$emailName, &$emailAddress, &$subject, &$message ) );
$emailAddress is the email address of a visitor when they use the form, which is var5. So if you want to subscribe that email address to a newsletter you'd set "For" in the AcyMailing action to [var5]. My recommend is as follows.
Global
Triggers: onBeforeEmailUser
User: User
Access: All Non-Registered Users
Action
For: [var5]
Subscribe: SELECT_NEWSLETTERS_HERE
That should subscribe visitors to the selected newsletters when they email a user using the email user form.
krileon
thankyou
