Last week a research analyst put the pieces together and came to the conclusion that Amazon.com is going to expand AmazonFresh into New York City. That means Amazon.com will be taking orders and providing same-day delivery to the nation's largest market. That may not mean much yet, but it suggests that the way eight million people buy groceries is about to change forever. The vision goes well beyond just groceries. Groceries are a Trojan Horse. The dirty secret of Amazon is that it really doesn't distinguish between a head of lettuce and a big screen TV. If Amazon can pull...