True, Web browsers bring in little direct revenue for their developers. Microsoft gives its browser away for free. But that belies a much more significant value. As the software the PC user sees, the browser is strategic. It can be a powerful marketing tool that helps promote Web sites by the mere mention of another locale on the Net or the placement of so-called ''channels'' that allow companies to deliver info directly to PC users.
Browsers also play an important role in defining standards for viewing Web content.
If a software company makes the predominant browser, it could dictate the way Web developers create their content. The company has been under government scrutiny since 1991 but so far has escaped with just a slap on the wrist. And, in spite of the consent decree, Microsoft's competitive position has become even stronger in the past two years. But the chorus of anti-Microsoft criticism is getting louder. And a win in this case could embolden Justice to bring a wider antitrust action.