At different scales

Network effects can function at different scales as well. The most important distinction is that between global and local effects. Local network effects appear in relation to the people in your immediate surroundings, such as your friends, colleagues and acquaintances. Because connecting with them is most important to you, you likely will use the application that they are already using, not the one most popular in the greater population.

An example of local network-effects is the usage of Apple computers in arts and design, while (until recently) basically everybody else used IBM-compatible PC's. Another example are social networking sites restricted to the employees of certain companies, such as Beehive within IBM (which has 50.000 users). Finally, the system of invites (that people can give out to friends) for Google Wave hopes to bring in pockets of befriended users (displaying local network-effects). As the variation in scale between these examples shows, the difference between local and global network-effects is relative, not absolute.

\section{Conceptions of critical mass}