What is a network effect on technology? Any examples for illustration?

Network effect
- Effect that a single person using a good or a service has on the total perceived value of that product or service for others. The more who use the product or service, the higher it's value becomes to the group
- is a phenomenon whereby a good or service becomes more valuable when more people use it. The internet is a good example. Initially, there were few users of the internet, and it was of relatively little value to anyone outside of the military and a few research scientists. As more users gained access to the internet, however, there were more and more websites to visit and more people to communicate with. The internet became extremely valuable to its users.