By every browser, that would include browsers on mobile devices, as well.
Since that page uses CSS, it would not look the same on my pocket pc, which has pIE 3.0 as its browser, and doesn't support CSS.
The background would be white, the text much smaller and located in the upper left, and no image anywhere on the page.
Now would someone want a page to look exactly the same when viewed on the tiny screen of a mobile device? Probably not. As a matter of fact, the mobile version should have less graphics and a few more options than the regular version.
Some of my blogs, for example, when viewed in a mobile browser, presents a link at the top of the page to give the option of skipping the content and going to the sidebar, and the entire site is a single column, with the sidebar content at the bottom.
With more people using web enabled mobile devices than ever before, it is becoming more important to remember those visitors when designing your site.
A site should look similar enough in every browser to be recognizable as the same website though. Imagine coming here in IE and seeing a nice blue themed forum and a bird mascot, and in Firefox seeing green and a snail. Your first impression after seeing it in IE first would be "I think I am on the wrong site".
But I believe it is ok to have those slight subtle differences in appearance that so many web designers lose sleep over, as long as the basic look is similar enough to retain the identity of the site. Your visitors won't mind that the bottom border is missing on long pages when viewed in IE but not in Firefox, and your loved ones would appreciate the extra time to spend with you that you would have wasted on something so silly. (now, if the footer and its content is missing, that's another story)
