You're missing the point. I'm saying that the reason for their success is not their own merit, but this random butterfly effect described in the linked study. It's a relevant discussion to have, since it indicates that there's a limit on how much you can control your own destiny in a social startup.
There is a butterfly effect, yes there is a limit on how much you can control your own destiny in a startup. But it's not an insurmountable obstactle. It means you can't just copy myspace exactly, improve it in a few minor ways, and expect to win over all their users.
In terms of competition, you may not realize what your competitor is doing that is stealing all your customers. From what I remember, the main competitor to Myspace was LiveJournal, and the networking features of myspace were far superior. Customized pages with photo albums and links to all the people you know are a lot more intrinsically interesting than an article about taking your cat to the vet. The other competitor I read about was friendster, which had a head start in social networking but was beaten because musicians and their fans used myspace. [0]
I remember the first time I saw myspace, all I really noticed was the music. The random user profiles barely registered, although I remember thinking it would be cool to have a band page with lots of fans attached.
