[catshirt]

Some more anecdotal evidence, my company (not mine; http://getglue.com) actually originally launched solely as a Firefox extension (primarily distributed through Firefox AMO).

This actually played some role in my decision in taking the job- this was still in 2008, when ignoring IE was essentially almost never an option. Better, was that the extension views were developed in CSS- so I was free to explore CSS3 much earlier in live projects.

More timely, even as a website we still have very little focus on supporting IE users.

IE makes up for < 7% of our total visitors, and IE6 only 4% of that. More interestingly, a lot of our visitors now come through consumer markets like HBO and Fox. I think the numbers are surprisingly low for IE already; but considering our market is no longer a techie market (quite the opposite), the numbers are somewhat more interesting.

That all said, I think this speaks true to the title of the article. It's just a careful decision you need to make- but fortunately not one that is impossible to solve quickly, should you make the wrong one.