The personal-computing revolution began with a promise: after decades of submission to centralized mainframes, ordinary users were now in control. Buttoned-up IBM loosened its collar, opened its new PC to accommodate hardware and software from a variety of suppliers, and even bought its operating system from a couple of Harvard University dropouts. To reinforce this message, IBM chose as its marketing emblem a look-alike of Charlie Chaplin-timeless hero of the harried underdog. It was a clever choice, and not inappropriate: the PC and other machines like it really did confer upon users a degree of control over information never before available. Twenty years later, technology industries are still promising us autonomy and independence.

It’s not that companies have ill intent. Manufacturers are offering hardware and code they claim will release the full potential of information technology: promoting creativity and productivity while making computing and the Internet secure and reliable at last. Their products address real problems-from brand counterfeiting and piracy, which cost billions, to malfunctioning equipment. But despite the benign intent, some features built into new generations of devices, like the Greek infiltrators in the belly of the Trojan horse, provide openings for intrusion and even conquest. Call it the Trojan mouse.

Measures to control behavior can depend on either accountability or incapacitation. Think of automotive traffic control. Until recently, most communities tried to control speeding with radar-equipped patrol cars. More recently, some towns have shifted to a strategy of incapacitation: they are making speeding physically difficult with increasing use of “traffic-calming” devices such as speed bumps. Police radar is a technology of accountability; it needs the courts to be effective and can be defeated at least some of the time by sensitive detectors. Traffic-calming structures, by contrast, are technologies of incapacitation: they limit passively what people can do with their vehicles.

Technology makers increasingly prefer incapacitation as a strategy of control. The software industry, for example, once used a double standard for enforcing its licenses: companies vigorously regulated software usage by commercial establishments while pretty much letting individual consumers do as they pleased. But as the distinction between home and office blurs, consumers now find themselves wrestling with the sort of constraints once intended mainly for corporate users. Microsoft is leading the way by beginning to license its Windows operating system for household use in much the way it deals with businesses: each machine must have its own paid upgrade to the next version. Users do have the right to continue running older versions of Windows, but they may find that new programs they want or need run only on the latest release. The result is “forced migration,” to use a stark metaphor dating from the mainframe era. Other technology and entertainment companies are also cracking down through incapacitation. Instead of paying more patent and copyright lawyers to take alleged infringers to court, they are modifying their products so that the user is physically barred from using them in unsanctioned ways. The traffic cop is giving way to the speed bump.