Roman and Medieval Shop Shelving
In Roman and Medieval times markets were a popular place for traders of many different backgrounds and origins to come together and sell their wares and produce. As markets opened and closed on different days of the week, the shops where on wheels often pulled by a horse or pony and could be set up and taken down relatively easily. Shop shelving was traditionally made from wood and there would be one main table display with 2 or 3 shelves at each side. Above the table a simple but sturdy wooden frame could hold some hanging objects like fruit or jewellery and a sheet could be draped over the top to give the stall owner some protection from the elements.
Victorian Shop Shelving
In Victorian times shops had become much better established in permanent shopping locations. High streets existed where a whole manner of different items could be sold and bought. Inside shops like chemists or sweet shops shelving was key to keep all the items apart. Still constructed from wood the shop shelving often incorporated drawers where soaps and ointments could be kept. Larger shops like greengrocers would have huge shelves to display vegetables and still used collapsible shop shelving to show their products outside.
Modern Shop Shelving
Modern shop shelving has changed considerably from the shelves of the past. Although shelves can still be bought made from wood many shops now favour metal shelving which is generally harder wearing and cheaper. Unlike the past Supermarkets are now common place with most towns and cities having several. In supermarkets the modern shelves are designed with being moved around a shop floor in mind, often featuring wheels. Markets still exist but instead of horses, vans can quickly unload a stall and its shelves in minutes and the same for packing it away.
I think it's interesting to see how shop shelving has changed depending on their application but their core uses are still very similar.