[yanw]

It's way too early to tell, ask again when it's visible to all users and integrated into all of Google's products and have the basic features of search and even decent (vanity) urls, not to mention not requiring an invite.

It's Google's social play, something it must have, a list of people you know and interact with over Google products. It's a work in progress and will yet unfold for some time.

And by the way, if any other startup got the numbers they have it would be dubbed a huge success, it's just that people like to speculate about everything Google as it gets them clicks.