He's blown away? Probably never seen any flash/flex applications in his life...

Maybe i'm a bit harsh :)

Flex is in a completely different department. Flex is impressive for sure, but to see what this crew has done with Javascript, it really is impressive.

If someone blind-folded your screen and told you 280Slides was a client-side app, you'd believe 'em. That's powerful stuff.

It's certainly technically extremely impressive.

The user experience, though, is not great, and certainly not worth the effort it must have involved. Why reimplement draggable, modal windows? What does that get the user? Must we really duplicate all the worst excesses of GUI interfaces just because we can? There are some really brilliant moments here (e.g. the ability to add pictures directly from Google Image Search) where the designers clearly bothered to think about how exploit the strengths of web-app-ness, but a little more of that and a little less slavish devotion to the GUI paradigm would not have gone amiss; there's too much "look what we can do." Just because you can doesn't mean you should.

Also, the author of the linked post claims that it is responsive, which it certainly is not for me; it feels very, very sluggish, 1+ second delays for mouse clicks to register.

It seems like nobody is really ready to give up the browser as a potential operating system. We have great technologies like Flex that simplify much of this work away, but folks keep hammering away at Javascript. Must be a sign.

Perhaps, we should just give in and give browser appropriate hooks into the operating system.

I agree that web apps that try to be desktop apps seem destined to come out the loser in that comparison. The interesting things in web apps are those that leverage the web itself. (Not, as you said, to take away from the impressive technical achievement here.)

Re fast vs. sluggish: which browser did you use? The next generation of browsers (e.g. Safari 3) is so much more responsive that the answer to this question would be revealing.

I've met the 280North team, and I was blown away when they showed me a demo of their stuff. However, while it visually looks like a desktop app, it still runs sluggish enough that I wouldn't mistake it for one. Fast computer and network btw.