Another meaning of snail mail

Reading Sarah Ogilvie’s The Dictionary People made me recall my one submission to the Oxford English Dictionary: snail mail, meaning not mail sent via a postal service but mail addressed without a ZIP Code. I found this use of snail mail in 2011, in a 1968 Life advertisement, and right away, I notified the dictionary.

Crickets.

The OED defines snail mail thusly:

(a) colloquial mail or post which takes a long time to be delivered; (b) Computing slang (originally U.S.) the physical delivery of mail, as by the postal service, considered as slow in comparison to electronic mail; a letter, etc., sent by post.

The dictionary has a 1929 (pre-ZIP) citation from The Indianapolis Star:

Snail mail ... Edward Ranton has just received a statement of account which the Wild Automobile Agency here mailed nearly three years ago.

All other citations, beginning in 1982, are about mail mail, as opposed to e-mail. Nothing about ZIP Codes.

Of course snail mail as a name for ZIP-less mail never caught on. But it amuses me to know that there was snail mail before there was snail mail.

Related reading
All OCA mail posts (Pinboard)