Which kind of application is appropriate for implementing with AJAX technique?
E.g. e-Commerce web site, enterprise portal, information publication application, forum, wiki and so on. I know for the new web 2.0 applications, such as wiki, AJAX is a better choice, and user can get a very amazing experience. But what about other traditional web applications developed with the traditional web techniques? Should we find out a way to align them with the new style?
Any web application is a candidate for using AJAX. Whether it's a good or bad candidate depends on it nature. AJAX is just another technique for writing web apps. The question is: does it add value to the user experience?
Wikis in particular seem not to be such a good candidate, but it's possible to AJAX-ify them, I suppose.
It's difficult to come up with hard and fast rules on when to Ajax-ify an app. In general most web apps/sites can benefit from at least a little more Ajax;-)
Sites like news, blogs, home pages and other text content heavy sites should be very cautious about using Ajax. There are many risks related to SE0, linking, accessibility and just plain annoying users that you need to consider.
Data centric web apps like ecommerce sites, CRM, accounting tools, social networking, email clients, workflow tools will generally benefit from heavier use of Ajax. But when proper usability and interaction design skills are applied.
In Enterprise Ajax we cover many of these issues in the latter half of the book. The case studies in the last chapter will likely be of of particular interest to see how other companies have benefited. The usability chapter points out a couple common pitfalls that show where you can go wrong with Ajax.