Share Mail (formerly Alternate Postage) provides a mechanism for businesses and organizations to use the mail to share information, not only with their customers but to have those customers send the Share Mail letters and postcards to other parties — without their having to affix a stamp. Postage is paid by the Share Mail account holder who produces and distributes the mailpieces.

Businesses and organizations who sign up for Share Mail can distribute Share Mail letters and postcards to franchises and customers (most businesses enclose the Share Mail piece within a mailpiece). Recipients of the mailpiece can then forward the enclosed Share Mail piece to others by depositing it into the mailstream as they would with other domestic, single-piece First-Class Mail. Share Mail relies on Intelligent Mail barcode® (IMb) technology to identify and count each mailpiece as it moves through mail processing equipment.

Prior to enrolling applicants must have the following:

1. USPS Business Customer Gateway account
2. USPS Enterprise Payment System (EPS) account
3. Valid Business Reply Mail or Postage Due Permit linked to the EPS account
4. Ability to print  a static or unique IMb on each mailpiece