This is an interesting thread by Li Jin and may change your narrative https://twitter.com/ljin18/status/1086738156840308736

Real-life networks are often very different from the idealized, uniformly distributed networks pictured in economics textbooks. Facebook exploited the fact that social connections are highly clustered at colleges as a “beachhead” to challenge much bigger incumbents (Friendster). By finding clusters in the network smaller companies can reach critical mass within those sub-clusters and then expand beyond.