Google is not so much trying to replace Microsoft Windows as render the traditional idea of the desktop-based operating system obsolete, a vision it can't realize as long as Microsoft controls the Web-browser market with Internet Explorer.

 
Although Google dominates Web search, one of the most basic internet functions, it has not yet found a way to crack the stranglehold Microsoft has long held on the browser market with Internet Explorer, which owns 75 percent market share. Google has tried to parry Microsoft's dominance by supporting Firefox, the open-source browser, but Chrome represents a new, frontal assault on Internet Explorer.

Microsoft, fresh off its stinging failure to acquire Yahoo as a way to attack Google's search position, isn't sitting on its hands.

Just last week, Microsoft released Internet Explorer 8, which includes a feature that makes it harder for websites—including Google (and Microsoft)—to track users' activities, a potential threat to Google's highly profitable targeted advertising. In a statement, Microsoft responded to the release of Chrome.

"The browser landscape is highly competitive," said Dean Hachamovitch, Microsoft's general manager for Internet Explorer, "but people will choose Internet Explorer 8 for the way it puts the services they want right at their fingertips, respects their personal choices about how they want to browse, and, more than any other browsing technology, puts them in control of their personal data online."

Google's entry into the Web-browser market has been widely anticipated.

As Google has matured, its torrid growth rate has slowed, putting the company under pressure to find new sources of revenue. As a result, in recent years Google has increasingly expanded beyond its Web-search roots into Microsoft's territory with Web-based applications for word processing, email, spreadsheets, and visual presentations.

But Google's track record building software has not matched its success in Web search—Google applications have yet to catch on broadly and have shown reliability issues—which is why the company faces an uphill battle if it wants to make a dent in the Web-browser market.

Chrome's debut should definitely worry Microsoft, said Rob Enderle, president of the Silicon Valley-based tech consultancy Enderle Group, but the onus will be on Google to show why people should switch from Internet Explorer, especially because most users don't really think about their Web browser as long as they can access websites smoothly.

"People typically don't switch browsers unless they are really unhappy with the one they are using, and Microsoft owns this segment," Enderle said. "Google will need to provide incentives to get people to not only try their browser, but [to] keep using it."