Supermarkets first became popular in the 1950's when many grocery shops became 'self-service'. Until then shops had all used the ' over-the-counter method' of selling where customers told a shopkeeper what they wanted, and he / she got if off shelving behind the counter.
The new supermarkets used an open plan arrangement, which allowed customers to browse along shelving to select goods for themselves
Today, most supermarkets are run by national or multi-national retail chains like Tesco, Sainsbury's, and Waitrose. They carry a wide range of competitively priced "own brand" as well as branded goods.