I have often thought that USPS has missed a great opportunity to provide a valuable service and make money while doing it.

I'm thinking about a webmail service with verified email addresses. You go the a local post office with a government issued picture ID, they give you an email address with a name based on you real name (with possibly some variation because of name collisions) with "usps" as part of the domain name. People receiving email from these addresses can have somewhat increased confidence that the email they're getting is, in fact, from someone they actually know.