The products are so easy to install and so tempting to buy.

All over the Internet companies are advertising that business owners and managers can watch their employees' computer usage.

"You have the right to know" says the bold headline on a site to sell the Spector CNE Investigator. It goes on to say "When your employees abuse their PC and Internet privileges, they are essentially stealing from your company. To protect the bottom line, you have the RIGHT to know and the RESPONSIBILITY to correct the problems."

While it might be tempting to bust employees who are shopping instead of working, it may also be counter productive because the deal between employer and employee is built on trust.

"The biggest impact is the extent to which employees are willing to contribute beyond what they are required to do," said Kurt Dirks, a professor of organizational behavior at the Olin Business School at Washington University in St. Louis.

Dr. Dirks has spent his career looking at trust and how it effects organizations.

He said employees who feel valued and trusted will put in the extra effort, researching past sales for customers on the returns phone line or adding a personal touch to customer service the way the workers do for Southwest Airlines. Employees who are engaged in the business will work longer days and on weekends if they need to.

The key, he said, is to weigh the potential costs of monitoring employees to the benefits of catching them goofing off or misusing the company's computer.

There are some ways in which it is appropriate to monitor employees' computer usage so that employees in investment firms are not handing around proprietary information, he said.

The calculation becomes "what do we have to lose against how does it change the behaviors of employees in a negative manner."

Dr. Dirks said transparency can help. If monitoring is a regular activity and employees all know, it mitigates the intrusion.

Monitoring employees is really nothing new, he said. In the past companies had employees provide progress reports, checked on phone usage and monitored mileage. Now computers and global positioning system devices can keep track of employees, their work and their whereabouts.

There also is nothing illegal about watching employees use of company's computers. According to Privacy Rights Clearinghouse, a nonprofit organization that tracks consumer privacy issues, it is legal for employers not only to listen to calls, but if employees wear headsets, to listen to conversations between employees. However, the laws in some states, including Pennsylvania, preclude taping any conversations without the express consent of the speakers. The organization also notes that e-mails sent on company computers are usually saved in the system even after they have been deleted by the employee.

But, while the computer-monitoring software makers are peddling fear of employees using their work computers to gamble or view pornography, the real question is whether they are doing their work.

According to Dr. Dirks, the biggest fear should be losing an employee's trust during busy times when the business needs to have all hands on deck giving a little bit extra.