[monfera]

> Leave data processing and business logic to the back-end, on the server

In general, this is not good. Of course there are specific applications where it's useful but in the general space of applications it would be very limiting.

For example, go to http://square.github.io/crossfilter/ and do the filtering on the 5MB data such that you wait for the histograms to be updated from the server. Instead of the tens of milliseconds, it might be seconds or tens of seconds if the server is loaded, i.e. orders of magnitude slower, not to mention unpredictable.

You can think of the network as a data flow constraint. It constrains latency, throughput, privacy and security; the constraints can be unpredictable (network outage; DoS, MiM attack etc.). There can be many good reasons for wanting part of your domain specific logic to fall on the client side.

In particular, dynamic media e.g. interactive data visualization, games and most interactive things that use data or modeling are best partly in the browser.

We're past the point where the rule of thumb was to do business logic on the server and the client only did the presenting of the view and acted as a controller.