Already I have to worry about: * Firefox 3+ (all OSes) * Safari (OSX, Windows) * Opera 9+ * Chrome 3+ * IE7+ * iPhone
There are just so many browsers I have to worry about. And even though I code for standards, every browser still treats every little thing slightly differently. I realize making something work in Opera if it already works in FF/Chrome is probably not too difficult, but sometimes little things can take up hours. So sorry Quirksmode, despite your well-written article, I will not even bother with any other browsers just because you say so.
You know when I will bother? When my users tell me that my app doesn't work well in platform X, browser Y and they would really want it to. That's when I will go beyond my basic list of browsers. Otherwise I'm just wasting resources developing for yet another platform.