Anonymous Email notifications.

Hey I love your plug in and its exactly what I need for my website. However, I need to know how to include the option for anonymous users to include their email address to get notified when an admin approves their questions and answers it. Similar to the notification option that is provided to users. I want to eliminate the need for creating user accounts on my website and have the question and answers to come primarily from anonymous users. The email they provide should not be visible to the public. It should only be used for notifying the user of question related updates.