Building a Large Network: Metcalfe's Law
Jaap de Jonge, Editor, Netherlands
Adding to #5 mentioned by Adedokun you should find a way to deal with Metcalfe's law
(1993), which states that the approximate value (Va) of a (telecommunications) network is proportional to the square of the number of connected users (buyers [b] and sellers [s]) of the system, or
Va = (b + s)2
Freely translated it means the more users participate in your network, the more valuable your network will become. So size is everything in building networks. One way this law will affect you is that in the beginning it makes it extremely tough to compete against existing networks that already have lots of users.
Metcalfe's law is applicable to any network, including physical networks (telephones), communication networks (the Internet), advertising networks (Google), social networks (Facebook), and even learning networks such as 12manage.