[corobo]

In my opinion what it would absolutely require is a 2-syllable, easy to remember, brandable, minimally SEO contested, .com domain

I realise that's not all it would take but so far I haven't seen any social network[1] without that succeed. It's some severe survivorship bias but I think it's probably a ground floor requirement

The real answer is that the person or people that have the secret sauce don't know they have the answer and are already working on it without knowing it'll be the next big social network. We'll find out in a few years if they don't give up on it

[1] The full fat social networks where you have all of your friends, not ones that target a smaller segment of the pie (e.g pictures - Instagram)

[roryisok]

How many "full fat" social networks are there though, really? In the English speaking world it's pretty much just Facebook. I don't think I'd even count twitter as a place where you have "all your friends", because most of the people that follow me are total strangers

[skinnymuch]

What are you thinking of besides FB? MySpace you can count. Sure Friendster came first but its popularity was pretty small compared to now. Is there any other example if you’re excluding Instagram?

[corobo]

myspace, friendster, twitter, bebo, orkut were the ones that came to mind

Not all great successes but more success than most