ChannelAdvisor's January data could be helping Amazon (AMZN +2.8%) rally: the firm's clients saw a 34.3% Y/Y increase in Amazon same-store sales, up from 29.8% in December. eBay's (EBAY +0.2%) growth came in at 18.8%, down from December's 22.2%. In a positive for Google (GOOG +0.1%), search ad-driven sales grew 1% after falling 18% in December thanks to a migration to Google Shopping. Shopping engine sales (inc. Google Shopping) rose 7.9%, down from December's 15.5%. SA contributor Paulo Santos, a long-time Amazon bear, argues Amazon benefited from favorable comps.