The Post Office plays an important role in delivering communications and packages in the US. The role they play however has not changed in light of computers and digital communications. They are not serving our current needs and are stuck in the role of providing services we no longer need.
Comprehensive reform is needed to release them from some of their current commitments (such as delivering residential mail 6 days a week) and allowing them to offer new services (such as secure encrypted email that carries the full tampering penalties that current US Mail provides).
In light of the legal structure that require delivery of notices via US Mail (other forms such as FedEx and UPS do not carry the same merit in court) this is basic infrastructure the needed in the US.