Throughout history, new communication technologies and social arrangements have enabled people to organize collective action on ever- larger scales. When this happens, human civilizations jump to high levels of complexity. This has been so since the printing press spread literacy beyond the ruling classes and enabled such new forms of collective action as science and democracy. For the past century, the wiring and unwiring of earth, followed by the emergence of the Internet, have enabled collective action to take place globally, simultaneously and virtually. Tomorrow, mobile communications and pervasive computing technologies could herald an era of smart mobs in which the devices we carry and wear link us in ways undreamed of today.However, if today\u2019s PC and Net users aren\u2019t vigilant, the future might not be as user-centric as the past. It all depends on what kinds of laws and restrictions will be burned into next-generation hardware and operating systems.Collective action happens when the aggregate actions of people add up to something instead of canceling each other out. The first humans who banded together to hunt big game; the first scientists who created a body of knowledge by pooling experiments and findings; the investors who invented the modern corporation in European coffeehouses; the people whose individual link choices add up to Google\u2019s page rank\u2014all have been involved in collective action.Today, collective action can involve devices as well as social contracts. Napster (intellectual property considerations aside) enabled 70 million computers to become, in effect, a giant music library. Seti@home (setiathome.ssl.berkeley.edu) and Folding@ home (folding.stanford.edu) enable millions of people to contribute their computers\u2019 idle computation cycles to searching for life in outer space or help biomedical researchers understand protein structure. Open-source software is created collectively, organized and coordinated online. What is the Web itself but the collective contributions of millions of people and their browsers, each creating a small patch of the planetary weave with their webpages and links?What new social arrangements can we build in a world of billions of devices, each more powerful than today\u2019s computers, interconnected everywhere, all the time, by wireless, high-speed networks? It is entirely possible that new industries, new ways of conducting science, powerful extensions of human capabilities will be invented by enthusiastic amateurs all over the planet\u2014most, but not all of them, doing it from their dorm rooms.Now that portable, wearable, wireless media make it possible for people to organize ad-hoc social networks, reputation software (like the buyer-seller rating system on eBay or the way posted messages are rated on Slashdot) could enable us to find common cause with the strangers around us as we move around a city and the world, similar to the way we connect with people online. Today, you walk down the street, surrounded by people you don\u2019t know but who might be able to offer a ride in the direction you\u2019re going, buy that bicycle you\u2019re trying to sell or entertain a request for a date. Social capital leaks into the air, wasted, and nobody notices. Could mobile, networked, computationally powerful personal communication devices weave us into social networks that haven\u2019t existed before, just as eBay brings buyers and sellers into a market that never existed before?A future of smart mobs and self-organized media is plausible as long as the owners of tomorrow\u2019s communications devices remain free to use the emerging media in any way they choose. However, a war over control of innovation might change all that, and the attack is already gathering force.You can see this multifront war in the following trends: The recording industry\u2019s attacks on file-sharing; the motion picture industry\u2019s sponsorship of digital rights management; the collusion of politicians, computer software monopolies and hardware manufacturers to burn "trusted computing" into future media; the moves by telephone and cable companies to fragment the Internet commons by refusing to carry traffic that competes with their own content offerings; the international adoption of versions of the Digital Millennium Copyright Act; the pressure from incumbent radio spectrum license holders to regulate future wireless communications technologies with laws formulated for radio of the 1920s.If those trends go unchecked, in a few years we will no longer be "users," free to reshape the technology as we choose, but "consumers," whose only liberty will be the freedom to decide which brand to buy. You\u2019ll have to get a license or permission from your boss if you want to make the Net or your PC do something it hasn\u2019t done before.Fortunately, the war isn\u2019t over\u2014and what we know, say and do now counts. Hundreds of millions of people have tasted the freedom, power and opportunity that personal computing and the Internet have made possible. Once they understand what\u2019s at stake, they can use the very media that is the spoil of the battle to self-organize collective action. Politicians won\u2019t try to get away with quite as much if enough people know about it, innovators will be motivated to make yesterday\u2019s centralized media obsolete as quickly as possible, and entire populations will reshape our media environment the way we did when we built the Web by posting webpages and listing our favorite links.The time to know, speak and act is now. The technology is in your hands. Use it well if you want to keep it that way.