Fancy widgets are nice, but my definition of a true AJAX interface is one in which the user can submit a form and see the results without waiting for a page refresh. The form is submitted to a Javascript function that communicates with the server in the background and then another Javascript function updates the page, based on the data it receives back from the server.
For example, AwareIM supports a tabbed form interface, but every time you switch to a different tab, you have to wait for the whole page to reload. With AJAX, all the tabs would be loaded at once and when you switch tabs, it would use Javascript to hide the current tab and switch to the tab that the user clicked on. This would make the interface much more responsive and would simulate the type of experience you would get from a desktop-based application.
I'm not familiar with RIA, though I may have used an RIA application without even realizing it. If it's more advanced than AJAX and provides more of a desktop-like experience, then I applaud you for moving in that direction, but I still feel that out-of-the-box, AwareIM should include basic AJAX functionality in its HTML interface. You might want to take a look at AJForm:
http://projects.aphexcreations.net/ajform/
This is an open-source AJAX framework that provides the exact functionality I described, without any additional bells or whistles. It's the purest and simplest AJAX implementation I've seen and could easily be incorporated into the existing AwareIM user interface, without changing anything else. It would simply give you the capability to do background form submissions, which would greatly speed up the interface.
