Maybe they mean "standards" support is very limited? I'm not an html parser builder, but it's all plain text when the browser, any browser, sees it. It's up to the browser to 'read' and convert that text into what should be displayed and where (although that is often up to the browser or affected by javascript). Explorers developers haven't always agreed with others about the meaning of W3C 'rules,' and they were also interested in creating a subset of functions that worked
only Exploder. Having a monopoly does have its advantages, after all.
So, it always makes me wonder what some of these sites are talking about when they mention one or another browser as being 'supported.' If they mean they develop their site on and test it on only one browser, that is not the same as saying they don't support another, specific browser. It only means they are too lazy to find out why only one or two browsers display their site the way the want it to be seen. To me, it also means they are still tied to the 'pixel-perfect-placement' paradigm of print media. But it also often means they like the way one browser does things and don't know how to get all browsers to interpret their code the same way.
When any browser scores very high on most standards tests
and a site warns that they don't 'support' that browser, it is obvious that they either don't know or care about 'standards.' And to me, that says they are not interested in their viewers, either, only what they want and the way
they want others to see it. "Excuse me. Did you know that I can completely block all of your presentational code?"
Rather like the html email question, is the point to give me information I want or to try to entertain me enough that I won't notice the sales pitch for a less than superior product?
If the site can make use of new technologies to provide easier usage in finding the information I want, great! Otherwise, stop wasting my time (and bandwidth)!
If I want flashy, gaudy colors and movement, I'll go visit a carnival...