What is the Network Effect? The value of goods or services increase as more people start to use that good or service.  (Telephone)

Feedback Loop Theory: Provides information to an organisation about the systems successes and problems. Predicting what your going to do before you do it.

What is a Dunbar number? A suggested cognitive limit to the number of people with whom we can maintain stable social relationship with. 150 is the suggested number of friends we can maintain.