Ajax Defined

You got your Ajax in my Ruby
Codified by Jesse James Garrett of Adaptive Path in “Ajax: A New Approach to Web Applications“, Ajax stands for “Asynchronous Javascript XML.” Essentially what Ajax does is move much of the smarts involving user-interaction from the web server to your web browser. This takes the form of an Ajax engine (a piece of Javascript code) embedded into a web page, downloaded to your browser, and springing into action upon arrival. Acting as an interaction broker, the engine takes care of all the whizbang interactivity you see (form input and validation, dragging-and-dropping, showing-and-hiding, etc.) while dealing with the web server (and it’s back-end database) as needed.

Well, this clears up a few things. Now it the questions is how does this help me? I did find this toolkit, Sajax, that includes a PHP backend.