280 Slides, by the same company, can be thought of as a tech demo for the platform.
When you think of what Adobe is doing, attempting to make it easier for design professionals to get building applications on the web and the desktop (via AIR), this puts them to shame. The web will be a better place with more web apps built on open source technologies like Cappuccino. If the next round of web apps are anything like 280 Slides, then things are going to get very exciting around here.
These kinds of technologies are going to allow for different kinds of web applications, which will push the envelope of what’s commonly accepted as possible. (Now all we need are some open standards to share data between them …)