Let people sign up and get their mail digitized to a secure, military-encrypted email address.
If people need to get packages, they can easily do so at the Post Office.
Introduce online-bill pay, short-term lending, and 3rd-party payment services to compete with PayPal.
Introduce video chat and messaging to compete with Twitter and YouTube.
And the page itself would compete with Facebook.
It is ludicrous, in this day and age, for physical mail to be delivered (An exemption can be made for seniors or the disabled).