Any big sites using Client Side XSLT?

Like other people have mentioned, Blizzard has many sites that are client side xsl. I would recommend avoiding client side xsl. It is a really cool idea, but there are many unusual bugs that you need to work around.

In Firefox, any javascript that uses document.write will destroy the DOM. Also, the noscript plug-in for firefox stops client side xsl. In both cases, the user will see nothing. There doesn't seem to be a way to detect this kind of error, so a fall back will not work.

In IE, if you have anything that does a 30x redirect to something of a different origin (going from http to https or crossing sub domains), you will get an error for violating the same origin policy. You did not really violate the same origin policy, but IE acts like you did. For example, if you go to http://foo.example.com/login and that does a 302 redirect to https://bar.example.com/login.xml, IE will treat the xsl as if it came from bar.example.com and it will treat the xml as if it came from foo.example.com. So you will need to revert to something like a meta refresh for your redirects.

These are the things that I came up with off the top of my head. It is a neat idea, but be aware of these issues.

I couldn't tell you in detail how it's implemented, but World of Warcraft is pretty big and high traffic, and their web site is implemented as you describe.

I don't know any big public Websites that use client-side XSLT transform (well, except World of Warcraft mentioned by Joel :-). So I cannot answer your question directly.

However, from time to time I was pondering the same question myself, and I have a hypothesis that the number of such sites on Internet must be very close to zero. :-)

The short version of my theory behind this hypothesis is this: with the exception of some pretty exotic cases, provision of client-side XSLT option is simply not worth the trouble. :-)