Philadelphia corner stores

One thing I've noticed in my new Fishtown location is that there are a lot of corner stores. Like "every other corner" wouldn't be a terrible approximation. Delis, bars, I think a salon, more delis/convenience stores... It's pretty neat. Both providing surprise as you walk around an otherwise residential neighborhood, and of course providing services to residents. No idea if they're all grandfathered in or if the zoning and parking codes would be friendly to buying a corner house and opening a business.