I recently prototyped a site using CSS that only Safari 3+ and FireFox 3+ could understand. I never loaded IE up once while doing it. Boy was it a pleasure being able to have a CSS stylesheet declare rounded borders with one declaration. The problem with supporting IE at all is that so few (almost none) of the CSS functionality that eliminates hacks we've been working with are available. Even IE8 isn't enough. So choosing to support IE at all means intentionally refusing to adopt features supported by Safari and FireFox. That is, unless you want an inconsistent experience for your users.

But why do we have to provide a perfectly consistent experience between desktop browsers?I'm starting to think that this is precisely what we should do to force MS to get with the times. Let your site degrade for IE in ways that do not break core functionality or fundamental design requirements. When users start figuring out that they can't see a prettier version of NYTimes because IE doesn't support @font-face, rounded corners, CSS transformations, and other advanced CSS functionality, many will decide to switch.

The difference between this approach now and how it was implemented in the 90s during the Netscape/IE wars, is that it's a best practice to degrade gracefully but retain important functionality now. The criticism of this strategy back then is that many sites simply did not work at all in one browser or the other. That would be unacceptable.