Google (NASDAQ: GOOG) has been experimenting with Google Express, a delivery service that picks up orders from stores and takes them to customers, for some time. Google Express even offers a same-day delivery service in some U.S. cities, including San Francisco. Big name retailers participating in Google Express include Target (NYSE: TGT), Walgreens (NASDAQ: WBA), Whole Foods (NASDAQ: WFM), Costco (NASDAQ: COST), Staples (NASDAQ: SPLS), PetSmart (NASDAQ: PETM), REI, and Barnes & Noble (NYSE: BKS).