15-05.
Network effect
Pattern description
A network effect (also called network externality or demand-side economies of scale) is the effect described in economics and business that one user of a good or service has on the value of that product to others. When a network effect is present, the value of a product or service is dependent on the number of others using it.
The classic example is the telephone, where a greater number of users increases the value to each. A positive externality is created when a telephone is purchased without its owner intending to create value for other users, but does so regardless. Online social networks work similarly, with sites like Twitter and Facebook increasing in value to each member as more users join.
Inventive problems
The customers should visit as few places as possible (it's the best - one place) to find information about products (goods and services) and suppliers, so as not to waste time on shopping, visiting companies or surfing the web.
The customers should visit many different places (shops, companies, Internet sites) to find the most complete information about products (goods and services) and suppliers.