The open-source Firefox Web browser may have been all the rage last winter, but some news headlines today proclaimed a possible end to its momentum. The grassroots favorite from the Mozilla collective seemed to be taking ever-larger nibbles at Microsoft's (NASDAQ:MSFT) heels. Now its long-term future seems far more uncertain., a website monitoring company, said that Firefox's market share slid to 8.07% in July from 8.71% in June. Internet Explorer's market share crept back up to 87.2% from 86.56%.

In the past, fellow Fools and I have taken interest in Firefox's entry into the long-running browser wars. Users' concerns regarding Microsoft's security issues over the past several years helped Firefox gain some ground -- just today, Windows users learned of a new threat, the ZoToB worm. Security has been a big issue for Internet Explorer users and a possible cause for users' defection to Apple's (NASDAQ:AAPL) Macs, small though that movement might be. (Apple's own Web browser, Safari, ran a distant third in's rankings. Its share increased a hair from 1.93% to 2.13%.)

Sure, these latest browser rankings are interesting, but paying too much attention to month-to-month machinations like these seems a bit like watching the grass grow. It was always likely that Firefox's growth would slow as the initial excitement over the grassroots upstart subsided. Meanwhile, with less buzz about Microsoft security problems, average users with less of a techie bent probably had less incentive to switch from IE. Also, as the head of said, Firefox's slump may just be an anomaly.

No one knows whether Firefox will continue to lose steam in the months ahead. If I had to go with my gut, though, I'd be willing to bet that it's still got a lot of life in it yet.

Further foxy Foolishness:

Alyce Lomax does not own shares of any of the companies mentioned.