You're right, but I think it speaks less to client side and more to current trends in server side technologies. The #1 feature of JSON is that it maps directly

You're right, but I think it speaks less to client side and more to current trends in server side technologies. The #1 feature of JSON is that it maps directly into the dictionary and array built-in types of all the popular "scripting" languages (Perl, Python, Ruby, Javascript, PHP). This makes it absolutely trivial to work with in both the browser and the server unlike XML which demands either DOM traversal to extract data (yuck!), or XPath (cleaner, but yet another thing to learn). I think this points to Ruby/Python/Perl/Javascript becoming more and more popular on the server side, even for "serious" apps.