eBay's (EBAY -0.1%) Now same-day delivery service has arrived on PCs (it launched as mobile-only), and is set to expand to Brooklyn, Queens, Chicago, Dallas, and the Bay Area peninsula (Manhattan and SF have been its first two markets). eBay has lofty ambitions for Now, foreseeing it as a same-day infrastructure for local retailers that can leverage existing retailer stores and warehouses. This is something Amazon (AMZN -0.7%), which just launched its $299/year Prime Fresh same-day service in L.A., could be hard-pressed to replicate, since it competes with many of those retailers. Initial partners for Now include Target, Home Depot, Best Buy, Macy's, and Walgreen.