Glancing through a list of web design mistakes, I ran across this interesting evidence of increasing web browser diversity, as number 6 on Jakob Nielsen’s list of Top Ten Web Design Mistakes of 2005:

6. Browser Incompatibility

Nielsen elaborates:

I admit it: during my spring 2004 seminars, I downgraded cross-platform compatibility to a one-star guideline (that is, “worth thinking about if you have extra project time, but not a priority”). At that time, almost everybody used Internet Explorer and the business case for supporting other browsers was getting pretty tough to defend on an ROI basis.

Today, however, enough people use Firefox (and various other minority browsers, like Opera and Safari) that the business case is back: don’t turn away customers just because they prefer a different platform.
— Top Ten Web Design Mistakes of 2005, Jakob Nielsen’s Alertbox, October 3, 2005

Apparently his customers informed him that the times had changed in the space of a year or two: web browser diversity has increased. That’s good news for all of us, because it means worms have a harder time spreading, which means better security for the entire Internet.

-jsq