In the larger populated cities of the time, merchants found a way to cater to busy customers who had little time or energy to prepare food during the evening. The variation in Chinese cuisine from different regions led caterers to create a list or menu for their patrons.
ZIP Code began on July 1, 1963, as scheduled. Use of the new code was not mandatory at first for anyone, but, in 1967, the Post Office required mailers of second- and third-class bulk mail to presort by ZIP Code. Although the public and mailers alike adapted well to its use, it was not enough.
Full Answer. The United States Postal Service began using two-digit area codes in 1943 in order to define postal zones in larger cities. Beginning in 1967, the ZIP code became progressively mandatory. The word ZIP comes from the acronym for Zone Improvement Plan.. The original ZIP code was composed of 5 digits.