The mouse was the original idea of Doug Engelbart who was the head of the Augmentation Research Center (ARC) at Stanford Research Institute. Engelbart's philosophy is best embodied, in my opinion, in the design of another device that he invented, the five-finger keyboard - with keys like a piano, used by one hand. The problem was, Engelbart's five-finger keyboard and mouse combination was very difficult to learn.

Each day as an AJAX developer seems to bring another helpful revelation: a new tool, a new gadget, a new way to reinvent the browser. But even when I'm confronted with a breakthrough as big as Firebug - the brilliant debugging tool for Firefox - in the back of my mind I'm reminded that the AJAX state-of-the-art is trailing behind the debugging tools that we've had in Java for years. With age comes maturity, and with Java's maturity has come a wealth of development environments, field-tested frameworks, and a rich set of strongly typed APIs.

Hard-nosed executives recognize that there are costs associated with any benefit. To convince today's upper-level decision makers to approve strategic investments, they need to hear more than phrases like 'essential to the business,' 'the results are too unpredictable,' and 'yields intangible benefits.' In the world of Web development, the move from HTML to AJAX-powered HTML can often be achieved at a relatively low cost, but there are both direct and indirect costs associated with AJAX that must be taken into account. A close analysis of these factors will enable business managers to make more well informed decisions when considering AJAX adoption in a particular application and across their organization.

Mobile AJAX is the extension of AJAX principles to the mobile environment, which includes other constrained devices such as gaming consoles or set-top boxes featuring Web browsers. While technologically the same thing, Mobile AJAX is looked at as a special case of AJAX, as it deals with problems specific to the mobile space including the areas of constrained devices and constrained Web browsers in general.