Jak pomocí snippetu vytvořit ‚Recent activity‘

Ahoj,
rad bych vytvoril neco jako je na foursquare.com (recent activity), kde se vzdycky prida nahoru novy item. V tuto chvili mam snippet, ktery obsahuje odkaz a ten pomoci javascriptu volam kazdych 15 vterin, jenze se mi invaliduje cely snippet coz nechci, ale chci pouze pokud bude last_id_v_db > last_id_na_strance tak pridat jeden item nahoru a ostatni posunout.

Nevite nekdo jak by jste na to sel?

V tuto chvili muj kod vypada nasledovne:

<?php
public function handleLoadActivities($number) {
    // last activities
    $model = new NewsfeedModel;
    $activities = $model->lastActivities($number);
    $this->template->activities = $activities;
    $this->invalidateControl('newsfeed');
  }
?>

<script>
// ajax loading activities
  var loadLink = $("#loadActivities").click();
  setInterval(function() {
    loadLink.click();
  }, 15000);
</script>

<?php
<a id="loadActivities" href="{link loadActivities! 6}" class="ajax ui-hidden">reload</a>
    <div class="newsfeed" n:snippet="newsfeed">
      {if isset($activities)}
      {foreach $activities as $a}
      <p>{$a->title}</p>
      {/foreach}
      {/if}
    </div>
?>