For a lot of random things, like... say, a suction cup thingy that mounts my smartphone to a car dashboard, I have no idea which stores are likely to sell such things, and they could have a wide discrepancy in prices. I can type into Amazon and see a list of products and prices, but if I want to buy one at a local retailer I might have to call three or four stores before finding someone who carries the thing I'm looking for. It would be really nice to have a search engine that can search products across brick-and-mortar retailers.