At first glance, PCs may seem like the ultimate productivity enhancer.

They let you plan and budget far more effectively than a calculator or table. They make it possible to keep track of people and things far more easily than a roster or list. They help you communicate far more efficiently than a typewriter or telephone. They can tap many more research sources than the largest collection of periodicals or books. And they make training far more compelling than words and pictures on paper.

But studies over the years haven’t praised PCs as effusively as the marketing materials of PC manufacturers.

According to a recent study by AOL and Salary.com, the No. 1 reason for wasting time at work is the Internet. The 10,000 workers polled admitted to wasting an average of more than 2 hours during each 8-hour workday, not counting lunch and breaks. Employers expect there to be some downtime, but this was about twice as much as employers expected.

The biggest distraction for respondents was personal Internet use, with 44.7 percent of workers citing Web surfing as their biggest distraction. The next biggest distraction was socializing with co-workers. Other distractions included conducting personal business, running errands, and making personal phone calls.

Here are other interesting findings of the study: The younger people are, the more time they waste at work. The three sectors of the economy in which workers wasted the most time were insurance, government, and education, in that order.

According to Salary.com (www.salary.com), employees reported some novel ways they wasted time while trying to avoid detection, such as walking hurriedly around the office to look busy (good cardio exercise) and staring blankly at their computer screens.

A study by Market Facts for the news site MSNBC.com (www.msnbc.com) found that employees spend more time browsing the Web for news during the workday than they do reading periodicals or newspapers or consuming other media. Fully 35 percent of respondents said they use the Internet at work for news and information. In contrast, 25 percent read newspapers, 21 percent browse journals and magazines, 17 percent listen to the radio, and 6 percent get their at-work news from television.

Some, perhaps most, of this time benefits the bottom line by keeping people up-to-date and aware of key trends and competitors’ moves. But the flip side is that information technology, including the Internet, leads to employees doing more work at home, which often exceeds their Internet use at work for nonwork purposes. One study from the University of Maryland found that workers with Internet access at home and at work used an average of 3.7 hours per week of work time for personal Internet use, and 5.9 hours per week on the Internet outside office hours for work purposes.

Still, there’s unquestionably room for greater efficiency in the way we use information technology tools in the workplace.

Employers should establish rational policies governing appropriate uses for email and the Web. Guidelines are usually more effective in the long term than prohibitions, including the use of programs that block verboten Web sites.

Email makes it easy to stay in the loop, but wading through scores of nonessential messages each day is a time-sink. Think through whether it’s more efficient, with any given communication, to use email, instant messaging software, videoconferencing, the phone, stopping by someone’s desk, the mail, overnight delivery, an airplane, or any other means, whether high-tech or old-school.

The Web can be an invaluable informational resource, but the temptation is great to jump from one site to another, each in turn less relevant to your work needs, whether it be to shop, check out sports scores, or engage in chitchat. Any time you surf, try to keep your purpose for surfing near the top of your mind.

Much productivity loss results not from using information technology for fun, but by failing to use all of its potential. Whether it’s an office suite program such as a word processor or spreadsheet, or an Internet service such as email or the Web, people often don't take full advantage of it because they don’t know how. Make sure that all those who need it, including top management, receive enough training to be efficient at the keyboard.

Technology, including information technology, is just a tool, as the word suggests. It’s how we use it that matters most. Despite their ever-increasing sophistication, PCs are ultimately just dumb machines, adding and subtracting zeros and ones, so it falls to us to be smart in managing them.