Look at the market share. And look at how much breakage report there is with Firefox vs. Chrome or Safari (not to say the return of "this website works better with Chrome" disclaimers, as if we were back to IE6).
There's a lot of websites that break for me on Firefox. Most examples are things like small businesses contact forms... I also had trouble with a kitchen design website. I can't remember what it was, but one just showed me a blank page unless I was on a Chrome-based browser.
half the time it's my choice of security settings and not Firefox. So... IMO %$#^% it - if a site doesn't support firefox I'm strongly disinclined to load up chrome to use it. There are lots of sites and lots of businesses.
