Backbone.js really introduces a new kind of data flow for Rails apps. Instead of data flowing like this:
Rails Model => Rails Controller => Rails View
It now flows like this:
Rails Model => Rails Controller => Backbone Model => Backbone Controller => Backbone View
I get confused. 5 components instead of 3—sweet. Why do I want backbone as part of my rails app? Just to ajax-ify everything? Will it reduce the load on my server?
The alternative to “5 components instead of 3” isn’t “just 3”. It’s “3 well-understood components on the server, and a bunch of jQuery/prototype spaghetti on the client that I really wish was better-organized and easier to extend.” If this describes your app, you might do well to look at Backbone.
UPDATE: To clarify, in the specific situation the author describes (exactly one model class, no relationships, basically the simplest "schema" one could create), the load will go down slightly. For real, interactive single-page apps (the kind backbone.js is targeting), the load will go up because apps requests data often, way faster than your current app which is limited by page refresh time.