Module
Is used to define and apply behavior to your application during the start process. Consist of config and run block code.
Dependency Injection
Is a term to you application giving you a value you need, example function with parameter, parameter are that DI.
module.constant
A constant can be injected everywhere. A constant can not be intercepted by a decorator, that means that the value of a constant should never be changed. module.constant register a constant service with the module.
module.run
Executed when all module have been loaded, excellent for execute system wide code that only need to be run once.
var app = angular.module('app', [])
.constant('VERSION', '1.0')
.run(function(VERSION){
alert(VERSION);
});