Milkman.

Groceries This sounds unlikely, but once GeekWire explains their headline a bit, it does make some sense:

Amazon patents the milkman

Amazon.com this week won a broad patent on technology that lets customers schedule product deliveries to their doorsteps or mailboxes on a recurring basis, without needing to submit a new order every time. The patent filing says this approach will be particularly useful to overcome “the challenges presented by the delivery of perishable goods or other consumables.”

“For instance,” the filing explains, “a customer may request delivery of one bunch of bananas every week and two gallons of milk every two weeks.”

Even having used Subscribe & Save a bit because the bulk prices are cheaper than even Costco, it hadn't occurred to me that this is very close to the service the milkman used to offer, albeit without the enticement of the special bottle of Barr's Cream Soda (the green stuff) if I've been well behaved this week.