But circles are nothing new. Facebook has offered several ways to break your network into smaller chunks for many years now, and it has worked constantly to refine them. And you know what? Almost no one uses those features. Only 5 percent of Facebookers keep "Lists," Facebook's first attempt for people to categorize their friends. Recognizing that "Lists" weren't great, last year the site unveiled a new way to manage your friends, called "Groups." I was optimistic that "Groups" would help to compartmentalize Facebook, but from what I can tell, few people use that feature, either.
You could argue that Facebook's failure to do this well doesn't augur anything for Google+. After all, Facebook's "Lists" feature is clunky to use—you've got to be constantly on guard about adding people to the correct list, and as your network grows and your relationships change, you have to do a lot of work to rearrange people. Facebook's "Groups," which lets other people manage your circles through rote tagging, is somewhat easier to use, but still apparently too much work for most people. If Google+ lets you manage these groups more easily, wouldn't it stand a good chance against Facebook?
I'm not sure. Google's "Circles" is more graphically entertaining than Facebook's "Lists." When you add someone to a circle, an animated +1 flies across the page, as if you've just got a Fire Flower in Super Mario Bros. But it is not intuitively easier to use. You've still got to manually corral your social network, and this can take a lot of time—especially because the initial suggestions in Google+ are populated by your Gmail contacts group, which means that there are hundreds of people to choose from (many of them duplicates). There's always the possibility that Google will make this process easier by adding some of its legendary algorithmic magic, using applied social-network theory to guess who belongs in your work circle, in your college circle, and in your personal ninth circle of hell. Perhaps if it does this well enough, people will see this as enough of a reason to share stuff on Google+ rather than Facebook.
I wonder, though, whether the whole theory of "circles" is misguided. It's very possible that we're all less obsessed with compartmentalizing our relationships than Google imagines. It's probably true that, as Paul Adams says, we keep multiple circles of acquaintances in real life. But it doesn't necessarily follow that people want to take the time to reflect that behavior online. After all, in the real world, managing your circles of friends is usually an implicit thing—you hang out with your school friends when you're at school, you hang out with your New York friends when you're in New York, you talk to your coworkers when you're at work. Unless you're planning your wedding seating chart, you don't usually go around categorizing and grading groups of friends, adding some people in and keeping other people out. And take my word for it: After you do it for your wedding, you'll never want to do it again.
There are three basic ways to share stuff online these days: You can do so publicly, for everyone to see; semi-publicly, for only your "friends" to see; and privately, for only designated people to see. Each of these modes is well-served by existing technologies: Twitter lets you share stuff with the public at large. Facebook lets you share stuff with your friends. And for private sharing, there's e-mail, texting, IM, Google Docs, the phone, and, from what I've been told, something known as "face-to-face conversation."
There are certainly people who want to control their networks at a much more granular level, and for those people, tools like "circles" or Facebook's lists come in handy. But the prevailing behavior on Facebook suggests that those features will attract only a minority. Most people are OK with one giant, chaotic circle, and spending a lot of time worrying about the consequences of sharing your stuff there is totally square.