I love Prism's approach - beats adobe's AIR hands downs by being true to the web (and web apps).. just mho.  I am using it for gmail, the one site i have always open but it looks like I can't run multiple instances on mac (running 10.5)? Any idea when that will arrive?

Yeah, I think they are different things though. AIR moves a lot more to the client.

Hey Alex.  There is an issue with XULRunner (The runtime engine for Prism, Firefox etc.)  See this bug report: https://bugzilla.mozilla.org/show_bug.cgi?id=402317

So, at this time, the mac version is limited to one instance of Prism.  I'll try to dig into the XULRunner bug that Mark Finkle mentioned.

As far as Prism v. Air and all that....  That sure was covered quite a bit in the ole blogosphere since Mozilla announced Prism.  In particular, Mike Chambers response got the discussion heated with this post - http://www.mikechambers.com/blog/2007/10/25/mozilla-prism-and-the-disingenuous-web/.  I personally found much of that conversation just silly... and witnessed several (most) comments from people who were not looking at Prism with a broad perspective and lacked an interest in how it relates to concepts of web/desktop hybrid applications.

When Apollo/AIR was released, I was plenty happy with what it brings to the table.  It's a great runtime to use with the powerful Adobe products for creating RIAs.  Whether or not I personally choose to use Adobe products and output to AIR is moot.

With Prism, I feel more... refreshed and excited about it than some of these other approaches we have seen come to light these past several months.  I am a web developer first.  I've used Rapid IDEs, such as Runtime Revolution, Director, MediaForge and others over the years.  But Web Development is my primary focus.  I totally understand the importance of desktop applications and always have kept tabs on the RIA scene.  One approach was to integrate native OS default web browser into the desktop client app (Windows would tap IE and Mac would tap Safari).  That gives you a window to the web and possibly some hooks to play with... but when compared to what Prism can do... it becomes obvious to me the elegance,  simplicity and power that it can bring.

I guess it depends if you believe the web is the platform... or if you prefer to adopt non-web standards by using Adobe or Microsoft products.  
Truthfully, a developer or team should be adept at all of these technologies and approaches to solving problem creatively.  depends on the job at hand.  But thats besides the point.

I like Mozilla.  I like Gecko.  I like XULRunner.  I like open source.  I like building for the web and being able to intelligently integrate to the desktop without having to build and maintain a "desktop version" of my web app.  Prism may be simple right now as far as what it can do with the desktop, but it is certainly not limited and this is only the beginning.  What Prism does now I think still does fill a void... bringing web applications into the desktop experience and providing a separate 'process' for each web app thus providing more stability on the users primary Web Browser and letting the web app run faster.    Tangler in Prism runs great as opposed to Tangler on Firefox with 5-10 tabs open.

The Prism approach to this just clicks with me.  And I think as more people get familiar with the project.... we'll see some good support and experiments.... and integrations with stuff like Google Gears etc.... good stuff.  Certainly calls for less reason to look at Air for porting your webapp to the desktop.
 

Thanks for your great reply. Without following all of the discussions going on around Prism I share your final sentiment - Prism clicks with me, too. It feels just right. Most web apps are so good because they are on the web -and Prism leaves them there

And since Gmail is the most critical for me that one will get the precious single instance I have. But I eagerly await for Weewar and Tangler to become the next two. Thanks again!
 

(ps> Weewar looks and works great already!)

This is from the lead developer of XULRunner:

"XULRunner has no problem opening multiple windows. What it does not do is
open multiple processes attached to the same profile. This is a design
decision and not something for a bug."

So, the solution will come in probably the next release of Prism that should support multiple profiles... one for each webapp. 
 

So it's a "design limitation"