It steps away from a classic web app model by moving a lot of app into the browser itself, which then interacts with server via AJAX. As it says on the SproutCore site:

After lots of testing, we have found that the most efficient way to server a SproutCore application is as a …. static web page!

This means that a “simple” static HTML page (which is easily served by Apache) makes browser do most of the work (i.e. server doesn’t have to generate the pages) which frees up server to respond only to AJAX initiated requests.

SproutCore is written in Ruby, but once you build the app it will generate a set of HTML, JS and CSS files, so you don’t need to know Ruby in order to use it. As the site says:

The code you write with SproutCore will resemble a desktop app written in Cocoa more than it will a web application written in Rails.

Another great thing about SproutCore is that it can be hooked up with any backend as long as it can communicate with it using HTTP. It can be anything: Rails, PHP, Perl, Java, ASP…

Actions speak louder than words, so take a look at the SproutCore demos which shows you exactly what it’s all about.

• SproutCore based photo gallery – iPhoto anyone?
• SproutCore sample controls – demonstrates what kind of controls are already available in SproutCore.

In next few days I will try to build a sample application powered by SproutCore and Rails to see how it goes. I will post my impressions here. After all if it’s something Apple used for Mobile.me – well, it can’t be that bad.