When talking about Web 2.0, Ajax has to be mentioned—plus moreover, of course, Ruby on Rails (RoR). This “revolutionary” web-app development framework also provides some bleeding edge Ajax functionalities, mainly through script.aculo.us‘ JavaScript libraries.
BTW: For having a nice first look at Ruby (the scripting/programming language used in RoR) this interactive shell tutorial (running with powered by Ajax) should be recommended to give it a try.
There’s a good online guide to Ruby book (by “why the lucky stiff”, maker of that tutorial) available for digging into it further, too.
