Many of those denominations were unusual fractional rates, such as 16.7 or 24.1 cents, used by bulk mailers and other businesses who also used precancels.

This time around, the bulk mailers seem pleased.

They would in effect be a parallel postal system for bulk mailers.

Many utilities and other bulk mailers with limited advertising needs have experimented with selling space in their bills to other companies.

A look through the morning's mail is discouraging: printed meters, or postage-paid permits, or transportation coil stamps used by bulk mailers.

At least for bulk mailers, and in a computerized world, such rate differences are easy to manage.

Use became mandatory in 1967 for bulk mailers.

An analysis of separate postal systems for bulk mailers is beyond the scope of this paper.

In 1967, these were made mandatory for second- and third-class bulk mailers, and the system was soon adopted generally.

(The European and Australian systems requires bulk mailers, in most cases, to receive "opt in" authorization from recipients.)