gap. reporter: with one new technology they can even anticipate what you might want. that s cakeo, a cupcake store in san francisco trying out tech built by a company called index. it helps retailers target products to you based on your taste. if you like red velvet, you probably like cream cheese as well as cocoa cake and we would recommend the pumpkin cheesecake. we looked to amazon as the backbone for a lot of things we ve done. a lot of it has to do with their ability to recognize who you are. reporter: they want to bring that experience offline. offline retailers need to be able to recognize you really on any channel you engage with them, whether it be online, social or in-store. reporter: the technology which you opt into is baked into their payment system to collect your buying behavior. it s also integrated into a store s app so you ll get push notification when you enter the store. it will say, welcome back, mark. it might suggest a new product. maybe provide you