 This system, which was intended to replace the deprecated POSTNET system, allows bulk mailers to use pre-printed bar codes to assist in mail delivery and sorting.Additional features, called Enhanced, or Full-Service, Intelligent Mail Barcodes allow for mail tracking of bulk mail through the postal system up to the final delivery Post Office.Critics of the universal service requirement and the statutory postal monopoly include several professional economists advocating for the privatization of the mail delivery system, or at least a relaxation of the universal service model that currently exists.