$routeParams

The initial setup:

<body ng-app="myApp">
  <ng-view></ng-view>
</body>
angular.module('myApp', ['ngRoute'])

.config(function($routeProvider){
  $routeProvider.when("/:message",
    {
      templateUrl: "app.html",
      controller: "AppCtrl",
      controllerAs: "app"
    }
  );
})

.controller('AppCtrl', function($routeParams) {
  var self = this;
  self.message = $routeParams.message;
});
<h1>{{ app.message }}</h1>

New here is $routeParams. Inside config(), $routeProvider will match the route against /:message, and the value of :message can be injected into the controller as $routeParams, and retrieved with a key of the same name.

The route parameters can be stacked and accessed in the same way:

angular.module('myApp', ['ngRoute'])

.config(function($routeProvider){
  $routeProvider.when("/:firstName/:middleName/:lastName",
    {
      templateUrl: "app.html",
      controller: "AppCtrl",
      controllerAs: "app"
    }
  );
})

.controller('AppCtrl', function($routeParams) {
  var self = this;
  self.message = $routeParams.firstName + " " + $routeParams.middleName + " " + $routeParams.lastName;
});