Web page visitors may want to bookmark certain state or pass it along to others. In pre-AJAX days it was a matter of simply passing a page URL. With AJAX, however, there's no standard way of conveying page state when some content have been pulled thru an AJAX call. One solution is to pass a "hash" parameter as if it was a request to move to an anchor within the page. That hash parameter can then be fetched processed by Javascript.