This weekend, I decided to goof off with Mozilla Lab's Prism Project. It is the Mozilla Foundation's implementation of the Site Specific Browser (SSB) concept. I set up or downloaded applications for Napster, Pandora and Gmail. Out of the box, it has novelty value, but little of practicality uniqueness. In its current form, you fire up Prism, provide a URL, and create one or more shortcuts. when the link is clicked, it will launch in its own private browser session, without toolbars, extensions, or navigation keys by default. This is nothing that Internet Explorer hasn't been doing for a long time and even Firefox can do most of it (with the unfortunate exception of not starting an independant browser session). You can also set a custom icon on it so that it "Feels" a little more like a desktop application. Prism's wiki indicates that you can do more with it, like custom styling, but I haven't seen anyone actually use these capabilities. The bundles I tried (like Gmail) simply create the shortcut and use a custom icon.
A great deal of the issue here is, no doubt, what Joel Spolsky calls the Chicken and the egg problem: to be interesting, Prism needs bundles, but no one is willing to create the bundles for Prism because Prism isn't interesting yet. If and when it catches on, the idea has potential. Gmail, for example, can run beautifully in the browser, but have nice tie-ins on the desktop, like showing a message count when it is in the system tray, start composing an e-mail when I click an e-mail link and allow drag and drop of files (particularly for attachments).
So far, it has had one very pragmatic benefit. As many Linuxers are aware, Flash and sound are both known to be somewhat problematic. Having downgraded to Ubuntu 8.04, Flash locks up sound when run in Firefox which means that, to run a desktop sound application (like, say, Amarok) I have to kill Firefox to release the lock. This works and, with Firefox's session management, is almost liveable, but is quite annoying. Using Prism for the Flash sites (which, for me, are few) allows me to kill the Prism "application" and release the lock, leaving my browsing and work untouched. This problem seems to have been sorted out in later versions of Ubuntu--to which I will not upgrade until suspend/resume and hibernate/resume work.However, this benefit really just makes up for two shortcomings elsewhere: the abominable state of Linux sound and the fact that Firefox does not run with separate processes for each tab (ala Chrome).
Mozilla's is not the only project attempting to work off of the SSB concept. A quick googling turns up many options, tough most are limited to either Windows or Mac OS X. The idea itself seems to be a bridge. From where and to where, it is difficult to say. We could be bridging from desktop applications to web applications. From web applications to RIA applications on the desktop. From web back to the desktop. The motivation probably varies by implementor. For Adobe, it is most probably a bridge from web applications to RIA. Once you are started with Air, it will probably be a lot simpler to get you over to move to Flex than it would be to simply jump directly from web programming to the hybrid world of Flex. Mozilla would rather see you use Google everything than see you use Microsoft products as this keeps the browser as the focus of your world. So, they want to create a bridge that eases the desktop oriented users (which is, for the most part, medium to older users, as the younger ones are used to doing everything over the web). to the web.
So, to sum up, Prism has some potential, though right this minute it isn't the biggest whoop in the world. However, it can still be kind of nice for odds and ends.