Commercial ".com" sites are dominating World Wide Web traffic as more and more companies rush to move their operations online, but Uncle Sam--the father of the Internet--is holding his own.

A dozen federal Web sites had more than 1 million visitors in April, with the U.S. Treasury, home of the Internal Revenue Service, predictably leading the pack. Indeed, the Treasury was the only federal agency to make the Web's top 50 sites in April, according to online measurement firm Media Metrix Inc.

The firm estimated that about a third of the Web's 61 million users in April--some 21 million people--visited a government Web site at least once. The data suggest that people make fewer, shorter visits to government sites than they do to general Web sites. The findings:

The No. 1 government site was the U.S. Treasury Department--mainly its Internal Revenue Service pages--drawing 3.7 million people at least once during the month when tax returns were due.

Second most popular was FedWorld, the clearinghouse that the Commerce Department launched in 1992 to allow people to search for information at many federal Web sites and agencies.

No. 3 was the U.S. Postal Service, whose Web site allows you to look up Zip codes, buy stamps, calculate mailing costs, or track delivery of Express Mail or Priority Mail items.

Others drawing heavy traffic include the National Institutes of Health, offering plenty of health-related research; NASA, one of the newsier and more ambitious federal sites; the National Oceanic and Atmospheric Administration, which publishes comprehensive weather updates; and the Library of Congress, which runs Congress's Thomas Web and the U.S. Copyright Web service.

By the People

The top 10 most-visited government sites:

Rank Domain Visitors*

1. Ustreas.gov 3.74 million

2. Fedworld.gov 1.85 million

3. Usps.gov 1.71 million

4. Nih.gov 1.54 million

5. Ca.gov 1.50 million

6. Nasa.gov 1.46 million

7. Noaa.gov 1.36 million

8. Loc.gov 1.22 million

9. Navy.mil 1.18 million

10. Army.mil 1.14 million

*Actual number of total users who visited the Web site at least once in April; visitors are counted only once.

SOURCE: Media Metrix