This is an article too loose, too imprecise, too full of buzzwords.

SOA is not middleware. It is an approach, and to implement it middleware may be useful.

All of the benefits you are describing pertain to the concept of Composite Applications, and have nothing to do with AJAX itself.

Of course, if on top of the benefits of a Composite Application you add AJAX (without directly invoking services), then it is better, but just and exactly in the same way as if you add AJAX to a regular web application. What AJAX delivers is usability, regardless of what your application does.

Now, on top of all this, I agree that having JavaScript directly invoking services is a nice model for composite applications. Probably this is what you meant, and you may like TIBCO General Interface, then. But what this adds is a convenient, universally supported platform with a dynamic language, which you may like or not.

And about service gateways - this is a whole debate in itself, but my opinion is that you do not need them to govern anything, neither in SOA or in anything else. Of course in AJAX you need them because of the cross-domain security constraints, but this is another issue. Trying to control something by centralizing it does not scale. ESBs are useful, but not in particular for monitoring and management. It is better to use decentralized agents. Ask AmberPoint or IONA.

The idea "AJAX + SOA: The Next Killer App enables faster, better and cheaper applications."

Well, first neither SOA nor AJAX are applications, much less killer apps. Second, we all know that of faster, better and cheaper you can only have any two of those threee at the same time. In other words: mission impossible.

To rephrase the non-existant app triumphs in mission impossible. Yeah, its a nice story, we all enjoyed the early Indiana Jones movies but I think true enterprise apps still benefit from a true architecture. AJAX is just another brain-damaged technology to get us around the deficiencies of HTML. In a whole decade, the IT industry has unsuccessfully struggled to break Microsoft's stranglehold on the desktop we use to access applications and good, clean solutions have become impossible, so we try to do with whatever would work (sort of) .. that's fine, but let's not get carried away in praise of this chaos.

Trackback Added: If SOA and AJAX is the Killer App, Who is it Killing?; Over at SOA Digest, AJAX + SOA is hailed as the new Killer App: We have business functionality represented in a reusable form - SOA services. We have ubiquitous connectivity - the Web. We have what's turning out to be the new application container - the browser. We have a programming model in the application container/browser - JavaScript. What I really want is a user-based composite application...