[velshin]

There's often a distinction between APIs intended for general consumption (platform APIs) and APIs optimized for JavaScript and/or mobile clients ("private" APIs).

A platform API tends to be stable, versioned, well documented, and "unoptimized" or strongly RESTful. GETing a resource (noun) returns just that one representation. e.g. GET /v1/user/123/profile or GET api.linkedin.com/v1/people/id=123

"Private" APIs tend to return more data in bulk, optimized to reduce the quantity of remote calls and improve page load times. The responses tend to be structured in a way that's easier for the client (browser/mobile app) to render content, usually by including more tangentially related data than a traditional REST resource would contain. e.g. a browser's load of https://github.com/rails/rails does GET github.com/rails/rails/graphs/participation

Twitter uses the platform API in the browser. e.g. GET api.twitter.com/1/trends/1.json

I'd be interested to hear from others leveraging APIs in their browser/mobile clients what they're using for MVC (e.g. backbone.js vs server side) and whether they've "optimized" their APIs for the client.