However, as Zeldman notes:

No hammer fits all nails, and no solution, however elegant, will work for every situation. But if we’re open minded, Andy’s proposal may work in more situations than we at first suspect.

Remember NS4?

This technique is very similar to what we used to do for Netscape 4 users when use of that browser started to tail off. We would serve our CSS using @import, knowing that Netscape would ignore that command and either get no CSS at all or a simpler stylesheet served with <link>.The Universal stylesheet for IE6 is a slight variation on the same technique.

As in the NS4 days, if and when to go this route depends on the situation. Of course you’re not going to do something like that if 30% of your visitors are using that browser. But what if it’s 6%? Or 4%? You wouldn’t choose this approach if branding an image were an important part of your site, but if the content is the focus (as Andy suggests), then maybe this is an appropriate option to consider.

Is IE6 worse than NS4?

Does anyone remember how much agony we went through in the last days of Netscape 4?  I’m starting to think that IE6 is dragging along longer than Netscape 4 did, and is harder to get rid of. With Netscape 4 there seemed to be fewer stubborn and pervasive obstacles to upgrading.

They at least need to know

I strongly believe that users of older browsers, where possible, should at least be informed that they are using an outdated browser. This situation is never going to change if users don’t even know that there’s a problem (since, you know, Microsoft is doing such a great job of explaining that). Even if their only recourse is to go to their IT department and complain.

This, again, is a matter of appropriateness. Of course I’m not going to put a message on the UW home page telling IE6 users to upgrade. But on the web development site? That would be appropriate.