List the four categories of non-store retailing and briefly explain each

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Although the overwhelming bulk of goods and services are sold through stores, nonstore retailing has been growing much faster than store retailing. Nonstore retailing falls into four major categories:
Direct selling, also called multilevel selling and network marketing, is a multibillion-dollar industry, with hundreds of companies selling door-to-door or at home sales parties. A salesperson goes to the home of a host who has invited friends; the salesperson demonstrates the products and takes orders. Pioneered by Amway, the multilevel (network) marketing sales system works by recruiting independent businesspeople who act as distributors. The distributor's compensation includes a percentage of sales made by those he or she recruits, as well as earnings on direct sales to customers. These direct-selling firms, now finding fewer consumers at home, are developing multidistribution strategies.
Direct marketing has roots in direct-mail and catalog marketing. It includes telemarketing, television direct-response marketing, and electronic shopping. As people become more accustomed to shopping on the Internet, they are ordering a greater variety of goods and services from a wider range of web sites.
Automatic vending offers a variety of merchandise, including impulse goods such as soft drinks, coffee, candy, newspapers, magazines, and other products such as hosiery, cosmetics, hot food, and paperbacks. Vending machines are found in factories, offices, large retail stores, gasoline stations, hotels, restaurants, and many other places. They offer 24-hour selling, self-service, and merchandise that is stocked to be fresh.
Buying service is a storeless retailer serving a specific clientele, usually employees of large
organizations, who are entitled to buy from a list of retailers that have agreed to give discounts
in return for membership.