The network effect is an important element in commerce, especially ecommerce. Which

one of the following is true about the network effect?

Also called Moore's Law, it is essentially the doubling of a product's value every $2$ years.

Also called Mellor's Law, it is essentially an economic a phenomenon whereby a product or

service gains additional value as more people use it$.$

Also called Metcalfe's Law, it is essentially an economic a phenomenon whereby a product or

service gains additional value as more people use it$.$

Also called Metcalf's Law, it is the ability of a product to adapt to a new system.