Lately there’s been a slew of new technologies promising to kill AJAX once and for all. Those technologies include Silverlight, Flex, and JavaFX. The problem with this theory is that all three require the user to install a plug-in. You cannot expect that a user will have your plug-in installed, and you shouldn’t expect the user to install your plug-in just because you tell them to.
Personally I dislike Flash web sites. They are slow and bulky and they ruin the bookmark/Forward/Back experience of the web browser. Now there’s promise that one of these new technologies will take over your browser, well I wouldn’t count on it.
I’ll grant you that AJAX itself also breaks the bookmark/forward/back mechanism, but that’s only when it’s not used correctly. I think there is a danger that these new technologies will be used to build entire web sites (as this is what is what we were told we could do last week at Mix 07). They should be used to enhance web pages, but don’t forget that visitors to your site want to be able to move around in a method that is familiar to them.