It used to be that surveillance on the job consisted of a camera at the loading dock. Now it includes retinal scans, fingerprinting, global positioning systems that track vehicles, and sensors on soap dispensers. Employers are monitoring email and Internet usage more than ever. All this has prompted concerns among privacy and workplace experts who worry that such monitoring devices represent an intrusion in workers' lives. One study found that 82 percent of employers keep tabs on employees through some sort of monitoring, including videotaping them at work or reviewing voicemails.

One lawyer has theorized that we're getting more and more used to surveillance, taking it for granted, which has a corrosive effect on civil liberties. But workers may not have many options. The courts have generally held that companies are entitled to keep an eye on the resources they provide.

The September 11 attacks have heightened security concerns, too.

Most employees sign paperwork when they take a job, agreeing to various surveillance policies, including the monitoring of computer usage. Even so, most are not aware of such policies. Most employees don't have a clear sense of what their rights are with respect to surveillance in the workplace.