Perhaps we should be a bit less hasty.
One of the incredible effects of Facebook's preposterously large domination of the social network space is that, relatively speaking, 10 million has become a small number. Where in almost any other field that kind of customer base would indicate a done-and-dusted success, in social networking it merely represents the early adopters. What kind of a tipping point do you need to get to in order to be a credible threat to a company with 750 million users?
The kind of growth you need to get to that tipping point presents another issue. An instant spike like the one Google+ received is both rewarding and worrisome. It is the sugary sweetness that led New Coke to beat Old Coke in taste tests. It is a fast-growing plant with a shallow root system. It is a shooting star.
The flaws in and resistance to the system have yet to manifest -- but they will. There are three problems that I can see with Circles. One is that it feels like work. Sure, the swishy drag-and-drop animation is fun for a couple of minutes. But maintaining any significant network within that sort of siloed environment requires a pedantic dedication to order that only exists in a small percentage of the population. Incidentally, these are the same people whose extensive song libraries are perfectly categorized -- no generic "Track 2" for this lot. I envy that level of tidiness, but let's be clear: those who achieve it are all too few.
The second problem with Circles is that the core concept of dividing people into circles is no more an accurate representation of the structure of our relationships than a one-size-fits-all "friend" is. Yes, it can be effective. If I'm posting a link to something that's NSFW, it's probably Not Safe For Work Circles either. But it also imposes a static, prescriptive order on a highly dynamic system. There are times when I want to be more intimate with my boss and times when I need to keep a particular friend out of the loop.
But the biggest problem for me is the lack of serendipity it engenders. If there is one thing social networks and living in public have facilitated, it's serendipity. Serendipity is a good thing. It's been well documented that people who talk to strangers tend to be luckier, and this also applies to communicating with our existing networks: the more open we are to the possibilities they offer, the luckier we are likely to find ourselves. This is what Twitter is exceptionally good at: the chance encounter that leads to a delightful and unexpected outcome.
When we put out a bit of information, we don't know who will see it, who will respond to it, and what kind of reaction it might provoke. And there is a thrill in the not-knowing; we feel titillated at the semi-passive public display of our inner workings. Facebook is the arena in which the struggle between our inner decorum and our inner exhibitionist unfolds. And that's why people haven't revolted entirely for lack of a better friend filing system on Facebook.
I congratulate Google for the undeniably successful launch of Google+. But this battle is far from over. I'd love to hear your thoughts and your experiences with the new network so far, in the comments or on Twitter.