I think the general difference is the location of the controller. On more traditional web frameworks, the controller is typically entirely on the server. The

I think the general difference is the location of the controller. On more traditional web frameworks, the controller is typically entirely on the server. The model twitter adopted moves the controller to the browser which just invokes services on the web server via API calls. Not really sure "web application architecture" unambiguously indicates "client side controller", but it does in this dialog when contrasted with "server side architecture".