[tryptophan]

Fun fact the US government subsidises mail spam. It's called media mail and for some inexplicable reason is 10x cheaper than normal mail.

[teraflop]

No, that's wrong. The media mail rate is for books and other similar media, and it specifically may not be used for advertising.

[bluGill]

That mail comes with rules. It presorted and so even though it is a lot cheaper to mail for them, because everything is in order there is a lot less work for the mail system and so they still make money on it in general.

[flymasterv]

That’s not what media mail is. Media mail cannot contain advertising.