Human beings are social creatures—not occasionally or by accident but always. Sociability is one of our lives as both cause and effect. Society is not just the product of its individual members; it is also the product of its constituent groups. The aggregate relations among individuals and groups, among individuals within groups, and among groups forms a network of astonishing complexity. We have always relied on group effort for survival; even before the invention of agriculture, hunting and gathering required coordinate work and division of labor. You can see an echo of our talent for sociability in the language we have for groups; like a real-world version of the mythical seventeen Eskimo words for snow, we use incredibly rich language in describing human association. We can make refined distinctions between a corporation and a congregation, a clique and a club, a crowd and a cabal. We readily understand the difference between transitive labels like "my wife's friend's son" and "my son's friend's wife, " and this relational subtlety permeates our lives. Our social nature even shows up in a negation. One of the most severe punishments that can be meted out to a prisoner is solitary confinement; even in a social environment as harsh and attenuated as prison, complete removal from human contract is harsher still.

Our social life is literally primal, in the sense that chimpanzees and gorillas, our closest relatives among the primates, are also social. (Indeed, among people who design software for group use, human social instincts are sometimes jokingly referred to as the monkey mind.) But humans go further than any of our primate cousins: our groups are larger, more complex, more ordered, and longer lived, and critically, they extend beyond family ties to include categories like friends, neighbors, colleagues, and sometimes even strangers. Our social abilities are also accompanied by high individual intelligence. Even cults, the high-water mark of surrender of individuality to a group, can't hold a candle to a beehive in terms of absolute social integration; this makes us different from creatures whose sociability is more enveloping than ours.

This combination of personal smarts and social intuition makes us the undisputed champions of the animal kingdom in flexibility of collective membership. We act in concert everywhere, from simple tasks like organizing a birthday party 9itself a surprisingly complicated task) to running an organization with thousands or even millions of members. This skill allows groups to tackle tasks that are bigger, more complex, more dispersed, and of longer duration than any person could tackle alone. Building an airplane or a cathedral, performing a symphony or heart surgery, raising a barn or razing a fortress, all require the distribution, specialization, and coordination of many tasks among many individuals, sometimes unfolding over years or decades and sometimes spanning continents.

We are so natively good at group effort that we often factor groups out of our thinking about the world. Many jobs that we regard as the province of a single mind actually require a crowd. Michelangelo had assistants paint part of the Sistine Chapel ceiling. Thomas Edison, who had over a thousand patents in his name, managed a staff or two dozen. Even writing a book, a famously solitary pursuit, involves the work of editors, publishers, and designers; getting this particular book into your hands involved additional coordination among printers, warehouse managers, truck drivers, and a host of others in the network between me and you. Even if we exclude groups that are just labels for shared characteristics (tall people, redheads), almost everyone belongs to multiple groups based on family, friends, work, religious affiliation, on and on. The centrality of group effort to human life means that anything that changes the way groups function will have profound ramifications for everything from commerce and government to media and religion.

One obvious lesson is that new technology enables new kinds of group-forming. The tools Evan Guttman availed himself of were quite simple—the phone itself, e-mail, a webpage, a discussion forum—but without them the phone would have stayed lost. Every step of the way he was able to escape the usual limitations of private life and to avail himself of capabilities from various professional classes to the general public is epochal, built on what the publisher Tim O'Reilly calls 'an architecture of participation."

When we change the way we communicate, we change society. The tools that a society uses to create and maintain itself are as central to human life as a hive is to bee life. Though the hive is not part of any individual bee, it is part of the colony, both shaped by and shaping the lives of its inhabitants. The hive is a social device, a piece of bee information technology that provides a platform, literally, for the communication and coordination that keeps the colony or from their shared, co-created environment. So it is with human networks; bee hives, we make mobile phones.

But mere tools aren't enough. The tools are simply a way of channeling existing motivation. Evan was driven, resourceful, and unfortunately for Sasha, very angry. Had he presented his mission in completely self-interested terms ("Help my friend save 4300!") or in unattainably general ones ("Let's fight theft everywhere!"), the tools he chose wouldn't have mattered. What he did was to work out a message framed in big enough terms to inspire interest, yet achievable enough to inspire confidence. (This sweet spot is what Eric Raymond, the theorist of open source software, calls "a plausible promise.") Without a plausible promise, all the technology in the world would be nothing more than all the technology in the world.

As we saw in the saga of the lost Sidekick, getting the free and ready participation of a large, distributed group with a variety of skills—detective work, legal advice, insider information from the police to the army—has gone from impossible to simple. There are many small reasons for this, both technological and social, but they all add up to one big change; forming groups has gotten a lot easier. To put it in economic terms, the costs incurred by creating a new group or joining an existing one have fallen in recent years, and not just by a little bit. They have collapsed. ("Cost" here is used in the economist's sense of anything expended—money, but also time, effort, or attention.) One of the few uncontentious tenets of economics is that people respond to incentives. If you give them more of a reason to do something, they will do more of it, and if you make it easier to do more of something they are already inclined to do, they will also do more of it.

Why do the economics matter, though? In theory, since humans have a gift for mutually beneficial cooperation, we should be able to assemble as needed to take on tasks too big for one person. If this were true, anything that required shared effort—whether policing, road construction, or garbage collection—would simply arise out of the motivations of the individual members. In practice, the difficulties of coordination prevent that from happening. (Why this is so is the subject of the next chapter.)

But there are large groups. Microsoft, the U.S. Army, and the catholic Church are all huge, functioning institutions. The difference between an ad hoc group and a company like Microsoft is management. Rather than waiting for a group to self-assemble to create software, Microsoft manages the labor of its employees. The employees trade freedom for a paycheck, and Microsoft takes the cost of directing and monitoring their output. In addition to the payroll, it pays for everything from communicating between senior management and the workers (one of the raisons d'etre for middle management) to staffing the human resources department to buying desks and chairs. Why does Microsoft, or indeed any institution, tolerate these costs?

They tolerate them because they have to; the alternative is institutional collapse. If you want to organize the work of even dozens of individuals, you have to manage them. As organizations grow into the hundreds or thousands, you also have to manage the managers, and eventually to manage the managers' managers. Simply to exist at that size, an organization has to take on the costs of all that management. Organizations have many ways to offset those costs—Microsoft uses revenues, the army uses taxes, the church uses donations—but they cannot avoid them. In a way, every institution lives in a kind of contradiction: it exists to take advantage of group effort, but some of its resources are drained away by directing that effort. Call this the institutional dilemma—because an institution expends resources to manage resources, there is a gap between what those institutions are capable of in theory and in practice, and the larger the institution, the greater those costs.

Here's where our native talent for group action meets our new tools. Tools that provide simple ways of creating groups lead to new groups, lots of new groups, and not just more groups but more kinds of groups. We've already seen this effect in the tools that Evan used—a webpage for communicating with the world, instant messages and e-mails by the thousands among his readers, and the phone itself, increasingly capable of sending messages and pictures to groups of people, not just to a single recipient (the historical pattern of phone use).

If we're so good at social life and shared effort, what advantages are these tools creating? A revolution in human affairs is a pretty grandiose thing to attribute to a ragtag bunch of tools like email and mobile phones. E-mail is nice, but how big a deal can it be in the grand scheme of things? The answer is, "Not such a big deal, considered by itself." The trick is not to consider it by itself. All the technologies we see in the story of Ivanna's phone, the phones and computers, the e-mail and instant messages, and the web pages, are manifestations of a more fundamental shift. We now have communications tools that are flexible enough to match our social capabilities, and we are witnessing the rise of new ways of coordinating action that take advantage of that change. These communications tools have been given many names, all variations on a theme: "social software," "social media," "social computing," and so on. Though there are some distinctions between these labels, the core idea is the same: we are living in the middle of a remarkable increase in our ability to share, to cooperate with one another, and to take collective action, all outside the framework of traditional institutions and organizations. Though many of these social tools were first adopted by computer scientists and workers in high-tech industries, they have spread beyond academic and corporate settings. The effects are going to be far more widespread and momentous than just recovering lost phones.

By making it easier for groups to self-assemble and for individuals to contribute to group effort without requiring formal management (and its attendant overhead), these tools have radically altered the old limits on the size, sophistication, and scope of unsupervised effort (the limits that created the institutional dilemma in the first place). They haven't removed them entirely—issues of complexity still loom large, as we will see—but the new tools enable alternate strategies for keeping that complexity under control. And as we would expect, when desire is high and costs have collapsed, the number of such groups is skyrocketing, and the kinds of effects they are having on the world are spreading.

For most of modern life, our strong talents and desires for group effort have been filtered through relatively rigid institutional structures because of the complexity of managing groups. We haven't had all the groups we've wanted, we've simply had all the groups we could afford. The old limits of what unmanaged and unpaid groups can do are no longer in operation; the difficulties that kept self-assembled groups from working together are shrinking, meaning that the number and kinds of things groups can get done without financial motivation or managerial oversight are growing. The current change, in one sentence, is this: most of the barriers to group action have collapsed, and without those barriers, we are free to explore new ways of gathering together and getting things done.

George W.S. Trow, writing about the social effects of television in Within the Context of No Context, described a world of simultaneous continuity and discontinuity:

Something similar is happening today, with newer tools. Most of the institutions we had last year we will have next year. In the past the hold of those institutions on public life was irreplaceable, in part because there was no alternative to managing large-scale effort. Now that there is competition to traditional institutional forms for getting things done, those institutions will continue to exist, but their purchase on modern life will weaken as novel alternatives for group action arise.

This is not to say that corporations and governments are going to wither away. Though some of the early utopianism around new communications tools suggested that we were heading into some sort of post-hierarchical paradise, that's not what's happening now, and it's not what's going to happen. None of the absolute advantages of institutions like businesses or schools or governments have disappeared. Instead, what has happened is that most of the relative advantages of those institutions have disappeared—relative, that is, to the direct effort of the people they represent. We can see signs of this in many places: the music industry, for one, is still reeling from the discovery that the reproduction and distribution of music, previously a valuable service, is now something their customers can do for themselves. The Belarusian government is trying to figure out how to keep its young people from generating spontaneous political protests. The catholic Church is facing its first prolonged challenge from self-organized lay groups in its history. But these stories and countless others aren't just about something happening to particular business or governments or religions. They are also about something happening to the world.

Group action gives human society its particular character, and anything that changes the way groups get things done will affect society as a whole. This change will not be limited to any particular set of institutions or functions. For any given organization, the important questions are 'When will the change happen?" and "What will change?" The only two answers we can rule out are never, and nothing. The ways in which any given institution will find its situation transformed will vary, but the various local changes are manifestations of a single deep source: newly capable groups are assembling, and they are working without the managerial imperative and outside the previous strictures that bounded their effectiveness. These changes will transform the world everywhere groups of people come together to accomplish something, which is to say everywhere.