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.

If you design an application that runs on Windows but doesn't look exactly like Windows, so the old argument goes, the effect will be unsettling for users. But sticking to the native look and feel (L&F) should not be the end-goal of designers.

Desktop widgets have been around for a very long time. The first set of desktop widgets were introduced by Apple back in 1983 with their release of Apple Desktop Accessories. Obviously Apple was way ahead of the curve, but these early widgets were not Internet enabled - the popular Internet, as we know it, didn't exist - so their utility was pretty limited.

For the past ten years application developers have been stuck with only two desktop client choices. Traditionally, they can choose either a very thin Web-client technology implemented in HTML and CSS, or a very heavyweight thick client experience implemented using traditional client/server (C/S) technologies (e.g. Java Swing, MFC). It wasn't until the introduction of RIA technologies (e.g. AJAX, Adobe Flex, Curl, and Silverlight) and widget engines (e.g. Yahoo! Widgets and Google Gadgets) that we were given more options.

If Gartner's assessment of AJAX's position on the Hype Cycle is correct, then the days when AJAX is the only game in town are over. Enter the age of what Anne Thomas Manes of the Burton Group calls 'Fit Clients' - a hybrid of Thick Clients (a.k.a. Fat Clients) and Thin Clients (HTML and RIA). Adobe AIR is definitely a Fit Client technology, but it's not the first and won't be the only player in this space.