The Mozilla Foundation’s entry in this particular race to conquer the desktop is called Prism.

While it shares the same core concept as Adobe AIR — running web applications on the desktop — the way it generates those applications is entirely different.

Previously known as WebRunner, the leitmotif of Prism is to give users a tool for creating desktop applications from any web application, in an extremely simple way.

If AIR opened the desktop’s doors to web developers, Prism opens that same door to everyone else.

What’s the point of this?

If you’re not familiar with web services like GMail, Google Calendar, Facebook, or Meebo, then not much. But if you use them every day, the picture changes. Prism spares you the process of opening your browser, typing in the address, logging in, and so on — instead putting your favourite web service a single click away (on your desktop, dock, Start menu, wherever you like). It also offers other benefits, such as better operating system integration (drag-and-drop file support, for example) and the ability to apply custom stylesheets to your application.

What are the downsides?

Its Achilles’ heel is that the resulting applications aren’t as visually rich as an AIR application can be. In principle, an app generated with Prism is little more than a website enclosed in a standard application window, whereas AIR (thanks largely to Flash) can have a completely custom shape and interface. A little creativity and CSS can work wonders, but classic web design has its limits.

• From a user’s perspective, it’s genuinely interesting to be able to turn your most-used services into applications — but the implicit “web aesthetic” it carries with it costs points in terms of user experience.
• With Prism, web developers would be relegated to a secondary role, their only real contribution being custom stylesheets to nudge the application’s look as far from a web feel as possible.
• From a marketing standpoint, its relevance would be virtually nil, as it lacks precisely the features that make AIR interesting in that context.

In short, while Prism is very attractive and above all useful as a user, as a web developer who also moves in the world of marketing, I see gaps that make me view it as a product at a very early stage, with a long road still ahead.

It’s still in development, but if you want to try it, you can download it from Mozilla Labs.

In the next and final instalment we’ll look at the third contender, Microsoft’s Silverlight.