The abandoned shopping cart is an e-commerce entrepreneurs’ nightmare. More often than not, shoppers browse an online store, load up their carts, then ditch them. Some studies estimate around two-thirds of shopping carts are abandoned just before the transaction is complete. In some cases, shoppers never planned on buying in the first place. In others, steep shipping prices or a long checkout process put them off. Sometimes, they wander off to other sites and forget about the stuff they wanted just minutes before. And, I’ll confess, I’ve had dreadfully lazy moments when I’ve given up on a pair of boots just because my wallet’s in the other room. Whatever the reason, e-commerce companies always are on the hunt for new ways to convince customers to seal the deal. One New York startup may have the answer: A single shopping cart for the entire internet.