Smart web clients; Ajax way..

We have been hearing a lot about Ajax (asynchronous JavaScript and XML) these days. It is for sure changing the way web clients are presented. Why go far; Google maps (so called poster child for Ajax) /Google Suggest are the few ones to implement Ajax, real time, but implemented extremely well. You will not feel a blink, that browser is talking to server real time, as user enters data.
Probably the driving force behind all this is XMLHttpRequest concept, which makes it quite possible. From the business front, Microsoft is been talking about smart clients for a quite a while reflecting their images on their Windows operating system.
I'm not sure how the scalability of Ajax works for business application type of products/Big data intensive/intelligent applications, where you have heavy database interaction, business models, data controllers, UI limitations etc. It might get clunky do a lot of work in Javascript/client side, if not designed right.

What is next ?

• Now people speculate; is Ajax a alternative for Flash, I don't think so. In fact they will be compliment each other in terms of sharing feature sets. xamlon.com went ahead collaborated the Ajax model with Flash and they call it as Aflax (Ajax+Flash). Look at their google maps equivalent in Flash .
• Toolkits and API for Ajax; We need toolkit and API's which support Ajax, which will learning curve
• Speculations; Sam Ruby about Ajax's other side.

I personally see a good potential in this model, to turn around the UI world, if not 360 degrees, atleast 180 degrees. It gives user of Ajax a better control over user anxiety on waiting for web application to load. Also gives more convincing power to UI seller to paint pretty picture effectively without much impact on performance.
I would watch for it, with experimenting Ajax way.