Most businesses are classified according to the industry they will operate in. Some of these will be large corporations that give attention to a specific kind of industry, such as Apple or perhaps Walmart, while technical writing and technical disciplines other folks specialize in a specific type of goods and services. Examples of industries in which businesses may operate include advertising and marketing, mattress creation, real estate, and oil. ExxonMobil, for instance, carries out business by providing oil to customers. Additional industries involve restaurants, shops, and other small businesses.