The last mile usually refers to the final connection between a telecom firm and its customers. It's been a challenge for all kinds of marketers trying to complete the distribution link to the customer's door (or office).
Clothing stores have a different "last mile," IMHO: The fitting room. If a customer takes clothing into the fitting room, there's a much, much better chance she'll take it home (assuming it fits). So what happens in the fitting room can make or break the sale.
Online retailers (and some store retailers) are using technology to show customers how clothing will fit. The auction/retail site eBay has an app to let you see how sunglasses will look before you buy. Virtual fitting rooms take some of the risk out of buying online, but when the customer is in the store, the fitting room is the last mile.
Macy's has tested a virtual fitting room in the store (see above), which not only lets the shopper see the "fit" but allows friends to see and comment, too.