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 with an