Yesterday, reports surfaced that Internet Explorer had suffered a dramatic drop in “market” share against Firefox, Safari, and Opera. Reports of IE’s demise, however, were quickly shown to be exaggerated. True, certain sites reported double-digit drops in the percent of their visitors using IE—but they were sites with highly technical audiences, the kind you would expect to be atypical early adopters. According to this article, IE’s drop among more mainstream users is much more modest: down from 95.5% to 93.7% (not quite three percentage points) since June.

But wait: there’s more to it than that. Sure, Firefox isn’t dominant, and has a long way to go before it is. It’s quite likely that it will never completely overtake IE. But that’s not really the point. The point is that, all of a sudden, modern browsers (especially Firefox, but also Safari and Opera) can no longer be ignored by organizations developing web apps.

Let’s look at the events that have brought us this far.

Firefox overtook IE in the feature department a number of months ago, but it was still a little rough around the edges, and the version numbers (below 0.8) reflected that. But then, just under three months ago (following a rash of new security bugs in IE and some worms that took advantage of those bugs) the U.S. Department of Homeland Security issued a recommendation that Windows users consider switching. It was a gentle recommendation that lacked teeth or urgency, but Firefox downloads went up immediately, and have continued at a higher rate than before.

93.7% still seems like a really daunting market share for IE. But turn it around: that’s more than one out of every 20 web users (also known as “potential customers” to commercial websites). Just three months ago it was slightly less than one in 20; today it’s trending toward 1 in 10. That’s significant.

Many companies write web applications that support only IE. Although I’ve never agreed with that strategy, I can see how some are convinced that it’s a reasonable one. But I suspect the problems with an IE-only approach will quickly become clearer.

The extent of IE’s dominance today is not the point. The point is how quickly other browsers can become too significant to ignore. It’s fairly easy for some to justify ignoring 5% of users. But can you afford to ignore 10%? If current trends continue, modern, non-IE browsers will have a 10% share by the end of the year. Their share will have doubled in six months.

And there are good reasons to think the trends will continue. Firefox’ lead in features continues to grow, and it’s becoming quite polished. The 1.0 release will appear soon, and that’s bound to bring increased publicity, interest, and acceptance. IE’s security woes have calmed a bit, but I don’t know anyone who believes they’re over for good. Meanwhile, Firefox has very few security flaws, and they tend to be fixed very quickly.

These thoughts began swirling in my head this morning, but that’s not the end of it. A little while ago I decided to download the Firefox 1.0PR release for my wife (she’s been using Firefox, and before that Mozilla, for a long time—and no, not because I told her to). When I saw the front page of it felt like the first rumbling of an avalanche. Today, in his column in the Wall Street Journal, Walt Mossberg wrote this:

I suggest dumping Microsoft’s Internet Explorer Web browser, which has a history of security breaches. I recommend instead Mozilla Firefox, which is free at It’s not only more secure but also more modern and advanced, with tabbed browsing, which allows multiple pages to be open on one screen, and a better pop-up ad blocker than the belated one Microsoft recently added to IE.

That’s big. I repeat: what matters isn’t IE’s share today; it’s how quickly things can change. When Walt Mossberg, Homeland Security,Fortune magazine, and the German government (among many others) are all saying “dump IE”—and the signs are that many people are switching to Firefox even prior to the 1.0 release—do you really doubt that IE could suffer major losses over the next year or so? Yes, they might be able to hold off this threat, but if you’re writing web apps today, do you want to bet on that? Do you want to risk having to explain why you’re turning away 15% of your potential user base?

(Oh, and one more thing. “Dump IE” is actually the sixth recommendation in Mossberg’s column, one of several things he suggests doing if for some reason you can’t follow his first recommendation. That first recommendation, which makes all the others unnecessary, is “chuck Windows altogether and buy an Apple Macintosh.” But that’s another blog.)