What's the big deal about AJAX?

Amazon's search engine and Microsoft's Outlook Web Access already used asynchronous JavaScript and XML, but the so-called AJAX technique has become hot since Google became a recent devotee. Why isn't it used more often for custom enterprise applications? Because it's really hard to build, experts say. Microsoft, for its part, is also a factor because of the limited use of its ActiveX controls. So whether AJAX is a fad or the future remains to be seen.

For more about AJAX:
- see this internetnews.com article