Fjax - Web 2.1?

Fjax is the lightweight, cross-browser, rapid-development methodology for Ajax-style web 2.0 development that puts a Flash engine under the hood (not in the presentation layer – read on) to handle realtime XML/HTML content updating.

Fjax enables web 2.0 development, with true, asynchronous (x)HTML content updating without page refreshes. The trick is, it does it with less than 65 lines of code and works in most browsers. It can process multiple streams of data simultaneously, and has an incredibly small footprint (4K!).