New Feature: Customer Editable Fields

When you add custom fields to your account, you can now choose whether your contacts should be able to edit that value themselves or not.

If you let them edit it, they'll be able to see and edit that information on the screen linked from the "manage subscription" link in the footer of emails.

This way you can let them tell you where they live, or when their birthday is, for example.

Go to Lists & Contacts > Fields, and add or edit one of the fields.