Cappuccino is an open source application framework for developing applications that look and feel like the desktop software users are familiar with.
Designed for Applications
Nobody will deny that there is a distinct difference between a web site and a desktop application. Similarly, we believe there is a big difference between a static web page and a full fledged web application. Cappuccino is designed for applications, not web pages.
Instead of doing all or most of the work on the server, Cappuccino applications do as much as possible in the client. A typical application would never reload, but rather send and recieve data using traditional AJAX techniques and then present that data in the client code. 280 Slides is the first Cappuccino application, and it's a showcase of what is possible with this new framework.
Instead of worrying about how to implement drag and drop, copy and paste (of text and objects), undo and redo, document saving, rich cross-browser drawing and graphics, and a slew of other features, developers are free to focus on specific problems like PowerPoint support, or Twitter integration, or whatever else makes their application unique and compelling.
How does Cappuccino Compare to Other Frameworks?
Cappuccino is not designed for building web sites, or making existing sites more "dynamic". We think these goals are too far removed from those of application development to be served well by a single framework. Projects like Prototype and jQuery are excellent at those tasks, but they are forced by their nature to make compromises which render them ineffective at application development.
With Cappuccino, you don't need to know HTML. You'll never write a line of CSS. You don't ever have interact with DOM. We only ask developers to learn one technology, Objective-J, and one set of APIs. Plus, these technologies are implementations of well known and well understood existing ones. Developers can leverage decades of collective experience to really accelerate the pace of building rich web applications.