Amazon's clever logistics hack

In the run-up to Christmas, Amazon has a logistics problem: millions of customers placing orders with free 2-day shipping, even though the packages are gifts that are going to languish in a closet for weeks.  This creates massive peaks in demand for Amazon, for no particular reason except that a lot of us happened to be  online at the same time. Amazon found a clever solution that lets them smooth demand, while also promoting one of their other products, and rewarding patient customers:

Nicely done, Amazon.