It will fail
And it will do so on several levels.
First, the Anonymous members who put themselves in charge of this project will be unmasked, either through some detective work on the part of a news group, another hacker group, or some guy they managed to tick off because of something they said or did or didn't say or didn't do (hey, nutjobs are legion).
Second, it will fail because there is no way that a social site, with the avowed intent of taking on Google and Facebook, can be created by one person, thus there has to be a group taking on the task. And, as every working person knows, the more people you put on a project, the more the chance of a jerk being part of said group. Said jerk will inevitably throw a spanner in the proceedings by outing the group, publishing names or something of equal jerkitude.
Third, and last, the sheer magnitude of this project is going to wear them down and break them. Behind their grandstanding and posturing, what we have is a group of people who come together to revel in a bit of chaos by doing what they think they do best : hacking other people's servers. This kind of activity, which they consider fun, is something they can do when they're ready and willing, and holds the thrill of success to drive them on. Building and managing a social site is light-years on the opposite of such 007-ness. It is a job, a mountain of work, with all the dreary day-to-day Mondays that that implies. They will have to be on their toes from day one, every day, without fail, else there will be issues. On top of that, they will have to learn to deal with unhappy people, something that posting a file accompanied by gloating text does not really prepare for.
All that said, I wish them luck with their reintegration project. And I wait for the day that their site gets hacked by the inevitable upcoming hacker group out to prove a point. I'll be interested in seeing the reaction of ancient hackers gone corporate.