config.json

{
  "vars": {
    "@gray-base": "#000",
    "@gray-darker": "lighten(@gray-base, 13.5%)",
    "@gray-dark": "lighten(@gray-base, 20%)",
    "@gray": "lighten(@gray-base, 33.5%)",
    "@gray-light": "lighten(@gray-base, 46.7%)",
    "@gray-lighter": "lighten(@gray-base, 93.5%)",
    "@brand-primary": "darken(#428bca, 6.5%)",
    "@brand-success": "#5cb85c",

addyosmani

Generally one implements notifications by listening for events on specific models but if one wishes to have a single global message interchange, it could be done as follows:

var pubsub = new Backbone.Model;

View1 = Backbone.View.extend({
  initialize: function(){
    pubsub.bind('custom event', callback);
  }
 // ...