Patrick Logan referencedPhilippe Bossut's notes on Learning AJAX with the pithy quote "Best data type to return: JavaScript instead of XML.". Midnight Coders just told me about their WebORB product which offers a "Rich Client" setup that amounts to an AJAX approach using the same strategy; the application server returns JavaScript to the client. The Voyager application server from ObjectSpace did the same thing in Java, as you can imagine, that required lots of gyrations. A couple of years ago, I was experimenting with DHTML and IE5 .HTC controls, and I found that JavaScript actually makes a pretty nice serialization format. That was actually the start of the realization that the Java/C# mindset comes with some pretty big disadvantages for the developer.