That this question is not so trivial as it might seems at the first look can be explained considering the following technologies:
OnLive (TM) for example: the principle is to play games on small powered devices in the browser by rendering the images on the server and send them as video stream to the client. The client only notice the interaction of the player, sends the interaction events (and only them) to the server, which renders the next image etc. Advantage: the calculation power of the server is potentially unlimited. Effects are possible crossing the border of all what is possible on a single pc. Let us call this "Black"
On the other side, complex applications like Google Docs (TM) and Saleforce (TM) are complex client side applications. There are a lot more, using HTML5 , giving the impression of a Desktop computer in a single browser. Let us call this "White".
And then, remember the famous approach of OpenCroquet, a Smalltalk based technology: the borders of client and server are blurred, because an OpenCroquet system is a set of more or less equal nodes which exchanges not data, but computation. There is no central computation instance, every node gets the same result by applying the distributed computation. Complicated mechanisms ensure that the results are the same for every node. Advantage: data are distributed, and computation need not that big transfer power. And this is a truly "Grey".
And now, what ? Black, White, Gray ?
The problem with Black is the requirements for bandwidth and latency. The problem with White is the different levels of code: the server code delivers code which runs in the client. This creates a real complicated meta structure.
As a hypothesis, my answer is to serve objects. Real objects, in the sense that they are independent (except to their communication with other objects) and complete entities. This would break the meta structure of the White approach, and using the good things from "Grey". In addition, if you let the objects be distributed opens space for using techniques from the Black approach, if you imagine that a big part of the object calculation may be done at the server.
At the moment, this are just ideas, but in the context of my "Coffee Game" they will become more concrete and reality, I hope :) But I don't want to think only in terms of bandwidth ore language structure, I search for the right way to prepare for the time where we think only in functionality, not in clients, servers, browsers. The age of Cloud and Web is still in the dawn phase, there is plenty room for better things :)
