Edit in JSFiddle

angular.module('telavox.test', [])
.factory('BroadcastingService', function($rootScope, $timeout) {
    $timeout(function() {
        $rootScope.$broadcast('myBroadcast', true);
    }, 1000);
    return {};
})
.controller('MyListLengthAddedController', function($scope, BroadcastingService) {
    $scope.received = false;
    $scope.$on('myBroadcast', function(ev, data) {
        $scope.received = data;
    });
})

<div ng-app="telavox.test">
    <div>
        <div class="controller" data-ng-controller="MyListLengthAddedController">
            Received event: {{received}}
        </div>
    </div>
</div>

</style> <!-- Ugly Hack due to jsFiddle issue: http://goo.gl/BUfGZ --> 
<link rel="stylesheet" href="http://twitter.github.com/bootstrap/assets/css/bootstrap.css">
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.0.6/angular.min.js"></script>
<style>
.error {
    color: red;
}
.controller {
    border: thin solid green;
    padding: 0.3em;
    margin: 0.3em;
}