[chockablock]

Recently saw a viral tweet with a picture of a political mailing posted on twitter with the address blacked out, but the USPS bar code (https://en.m.wikipedia.org/wiki/Intelligent_Mail_barcode) showing (looks like a comb with broken teeth).

They obviously didn't know the barcode contained the precise house address of the recipient (presumably the user's home address). Anonymization is hard!

[jsymolon]

Like SSNs (with a defined purpose), IMbs "use" is to help the USPS sort and deliver the mail without manual handling.

Large mailers (billions of pieces per year) get a postage discount by applying such barcode to all the pieces. (edit: any mailer can get the discount. it just adds up for the larger mailers) Those pieces are delivered to USPS facilities, dumped into the auto-sorters and end up at the local post office with no human handling.

It should not be used for anything else except handling mail.