Edit in JSFiddle

var data = [
    {name: 'jug-montpellier', url: 'http://jug-montpellier.org/', date: 'tous les 3eme mercredi', icon: 'http://www.jug-montpellier.org/public/images/logo.png'},
    {name: 'devoxx', url: 'http://www.devoxx.fr/', date: '20 Avril 2016', icon: 'https://pbs.twimg.com/profile_images/587897238568968192/NMdj4LCC.png'},
    {name: 'KiwiParty', url: 'http://kiwiparty.fr/', date: 'Juin 2016', icon: 'http://kiwiparty.fr/xmedia/kiwiparty/2015/logo-kiwiparty.svg'},
    {name: 'mix-IT', url: 'http://www.mix-it.fr/', date: 'Avril 2016', icon: 'http://www.mix-it.fr/public/images/mini-mixit.png'}
];

var app = angular.module('app', []);

app.controller('LittleCtrl', [
    '$scope', 'LittleSrv',
    function ($scope, LittleSrv) {
        $scope.confs = LittleSrv.getConfs();
        $scope.newConf = LittleSrv.buildConf();
        
        $scope.addNewConf = function() {
            LittleSrv.addConf($scope.newConf);
            $scope.newConf = LittleSrv.buildConf();
        };
    }
]);

app.factory('LittleSrv', [
    function() {
        var confs = data;
        var listenerConfs = [];

        return {
            buildConf: function() {
                return {};
            },
            getConfs: function() {
                return confs;
            },
            addConf: function(newConf) {
                confs.push(newConf);
                for(var i=0; i<listenerConfs.length; i++) {
                    listenerConfs[i]();
                }
            },
            onConfAdded: function(callback) {
                listenerConfs.push(callback);
            }
        }
    }
]);

app.controller('CountCtrl', [
    '$scope', 'LittleSrv',
    function ($scope, LittleSrv) {
        $scope.nbConfs = LittleSrv.getConfs().length;
        LittleSrv.onConfAdded(function() {
            $scope.nbConfs = LittleSrv.getConfs().length;
        });
    }
]);

<div class="app" ng-app="app">
    <div ng-controller="CountCtrl">{{nbConfs}} confs</div>
    <div ng-controller="LittleCtrl">
        <ul class="confs">
            <li class="conf" ng-repeat="conf in confs">
                <img class="conf-img" ng-src="{{conf.icon}}" />
                <a class="conf-url" href="{{conf.url}}" target="_blank">{{conf.name}} le {{conf.date}}</a>
            </li>
            <li class="conf">
                <input class="conf-input" type="text" ng-model="newConf.icon" placeholder="src image" />
                <input class="conf-input" type="text" ng-model="newConf.name" placeholder="titre" />
                <input class="conf-input" type="text" ng-model="newConf.url" placeholder="url" />
                <input class="conf-input" type="text" ng-model="newConf.date" placeholder="date" />
                <input class="conf-input" type="button" value="Ok" ng-click="addNewConf()" />
            </li>
        </ul>
    </div>
</div>