Zuckerberg started a social network at HARVARD. What part of being doesn't involve being part of building a social network at Harvard not involve "being part of the right social circles"?
linkedin started by getting top vc's and ceo's in the valley to use their product. Now if you asked me which company were more likely to succeed I would guess Linkedin. Regardless not taking anything away from Linkedin or mr Hoffman but there are things a company can do to increase their probability of success.