According to the Mozilla Foundation, developer of the browser, it has only been about 100 days since Firefox was released, a fact that highlights how quickly it has spread across the Web and around the world.

As Firefox succeeds, it is chewing into Internet Explorer's dominating market share, which is 92.7 percent, compared to Firefox's 4.8 percent.

Browser watchers are waiting to see if Firefox can maintain its momentum into the next release, scheduled for April, and garner more downloads past that.

Security Force

Part of the reason for the robust adoption rate for Firefox has been security, said Yankee Group analyst Jim Slaby.

Security reports about Internet Explorer have prompted many individuals and some universities to go with Firefox over IE.

But as Firefox becomes more popular, it is likely that it will become a more attractive target for malicious hackers, Slaby said.

"It's ironic that people are turning to Firefox because it's secure," he said. "Because the moment it becomes really successful is when hackers begin exploiting it more diligently. When it gets more market traction, it will be targeted."

Some Doubts

As Firefox draws more devotees, some analysts have warned that the open source darling is not yet ready for the corporate space, and have urged caution in making it the default browser for a company.

In early February, Gartner posited that Firefox usage is being driven by factors that are not inherently sustainable.

The research firm added that Firefox usage will grow until Microsoft chooses to respond. Most likely, companies and individuals could opt for a mixed browser environment until IE is revamped.

Strong Appeal

Despite concerns over security and Firefox's ability to maintain its popularity, for now it seems that the underdog browser has quite a bark.

Recent reports on two Scandinavian Web sites have implied that Nokia may have switched to Firefox from IE, despite assurances from Microsoft that it would be refreshing the browser design some time this year.

"No matter what Microsoft might do, you'll still see a lot of people kicking the tires of Firefox and checking it out," said Slaby. "There are many indications that Firefox could get wider adoption than many people have anticipated."