I’m not sure if this is something that was fixed in 10.4.3, but Safari (Apple’s built-in web browser) now passes the Acid2 test. What is Acid2, you may ask? Well, to quote from the website, Acid2 is “a test page, written to help browser vendors ensure proper support for web standards in their products.” I do know that Safari did not pass this test in the original 10.4 Tiger release.
If you see a smiley face with the words “Hello World!” above it, then the browser passes the test. I don’t think Internet Explorer passes, and I know that Firefox 1.0.7 doesn’t pass either.