Submitting your AWeber email address to an FFA page with your URL is spamming and is not permitted.
FFA sites post only your web site address, not your email address. They only request your e-mail address in order to email you personally.
If you were to submit your AWeber email address, when an FFA site owner sent you his initial welcome email, he would be added to your AWeber autoresponder as a subscriber. He would then receive email from you through your account.
But he never asked to be added to your list or to receive email from you! Any e-mail your AWeber Autoresponder sends to him would be spam.