Mass media social networks are a winner-take-all game. All but one candidates will fail, and the success of that winner is all but certain to be based on a mix of ideosyncratic or non-apparent characteristics, though founding cohort can be and has been a major success factor.
Two of the largest online social networks to date have emerged from the highly-selective university space: Usenet (UCLA, Stanford, Berkeley, MIT, UI, Rutgers, etc.), and Facebook (once: literally Harvard).
Google+ might have been able to grow from its tech roots. My sense is that Google's marketing-and-advertising focus (and community), as well as gross mismanagement, doomed its attempt, nudged with some active antipropaganda from other sources, notably Facebook. That's not to say it would have succeeded, but there were numerous self- and externally-imposed injuries.
Two of the largest online social networks to date have emerged from the highly-selective university space: Usenet (UCLA, Stanford, Berkeley, MIT, UI, Rutgers, etc.), and Facebook (once: literally Harvard).
Google+ might have been able to grow from its tech roots. My sense is that Google's marketing-and-advertising focus (and community), as well as gross mismanagement, doomed its attempt, nudged with some active antipropaganda from other sources, notably Facebook. That's not to say it would have succeeded, but there were numerous self- and externally-imposed injuries.