In a cover story on Jeff Bezos and Amazon (AMZN), FastCompany's J.J. McCorvey observes the company's new AmazonFresh grocery service (offered via its $299/year Prime Fresh free shipping plan) is a "Trojan horse" meant to give Amazon's broader same-day delivery efforts needed scale.
Amazon is also hoping its same-day infrastructure (replete with Amazon trucks) will increase its appeal to 3rd-party sellers (now responsible for 40% of unit sales) by lowering delivery times. Merchants already cite access to Prime as a reason for outsourcing fulfillment to Amazon (and giving a ~20% cut).
EBAY could prove a formidable same-day rival. Instead of building its own soup-to-nuts infrastructure, eBay is relying on dozens of offline retailers (inc. major national chains) to help handle fulfillment. Google is also dipping its toes into same-day.
Currently available in L.A. and Seattle, AmazonFresh is expected to expand to 20 more markets, including some international ones. SunTrust recently predicted an NYC launch will happen in 2014.
Also mentioned by McCorvey: Amazon is now able to ship items less than 2.5 hours after an order is placed; and wants to further lower than number; Prime now covers 15M+ items (up from 1M in '05); and Amazon is still "evaluating" how to use Kiva's robots.