What's AJAX?

People tell me that they just love my ajaxified site. I don’t get it. My understanding was that ajax stands for asynchronous javascript and xml and it allows you to communicate with the server without reloading the page. No where on my site is this technique ever used. Was my definition incorrect? If so, what is Ajax?

I see more and more people referring to libraries like moo.fx and scriptaculous as ajax. Granted scriptaculous does have some ajax controls but no one is ever actually talking about them. They’re talking about the drag and drop and sortable list effects. The moo.fx library by itself (meaning without moo.pack.js) does 3 things, changes the height, width, and opacity of an element. How is that ajax? I just think its fancy javascript.