Not to be confused (as I was) with FOB, free on board, a term in commercial sales law, especially wrt international shipping: https://en.wikipedia.org/wiki/FOB_(shipping) I wouldn't be surprised if the similarity in acronyms isn't coincidental as in the abstract there's some conceptual, if not legal, overlap, and Amazon may have been aiming for something that read like authoritative legalese--the legal department must "always be selling" no less than the sales department. But neither would I be surprised if it was coincidental.