When Apple introduced the iPhone, the story was that we didn't need native apps, instead the Web was the application environment and apps should just be written to run in a browser (Mobile Safari). This didn't last too long as Apple succumbed and the App Store was born and by all accounts, other than developers who can't get their apps approved, it has been a wild success. I have to wonder though if Steve intentionally made the whole process somewhat onerous to try to encourage folks to still write to the Web as a better and preferred way to get apps to the device.
The success of Apple's App Store has led to other "app stores" or "marketplaces" from mobile phone providers to carriers to the Java Store and more. So it isn't terribly surprising to see Intel launch a netbook app store, although I have to wonder if the motivation is just to keep up with the Jetsons or if this is the right model for netbooks. After all, isn't the point of the netbook to leverage Web applications? If so, is having a store for native apps really needed or desired? It would seem it is just giving users a crutch to avoid making the transition to the world of applications on the Web.
So why is this? It is a combination of several things including more developers being comfortable and adept at creating native apps, HTML5 not being ready yet (an excuse for the original iPhone, less of one now), and users being familiar with native apps or fearing not having access if they are out of range of the network so thinking they have to have them.
But there are significant advantages to a world of Web apps.
For developers, while it may never truly be write a single Web app and use it from any device, there is a whole lot more reuse and leverage from creating apps for the Web rather than creating N native variations. Particularly when platforms like the iPhone refuse to support Java or insist on requiring development in Objective C. Being able to have an addressable market of multiple mobile and desktop platforms is a huge advantage over targeting one specific platform.
For users, using Web apps allow access to the same app and data from any device without having to perform complex and error prone synchronizations. Whether you need to access your e-mail, calendar, documents, games, whatever, being able to do so from multiple devices should be a huge benefit if users can just get over the notion that they don't have the app in their possession on their device.
So when will the transition occur? It will happen first with mobile and lighter weight "netbook" type of devices. These are (or should be) designed for the Web and will have less storage and general horsepower to run native apps and so are well suited to it. It perhaps will take something like Chrome OS to do it as other Windows, Linux, or OS X based devices will always have at their core an OS built for native apps. Chrome OS will change this as far as we can tell.
In the mean time, go ahead and make it a point to ask "could this be a Web app" when creating that next application. You may be surprised what is possible and how many more devices and users you can reach.