public static function InformNotifications($Sender) {
      $Session = Gdn::Session();
      if (!$Session->IsValid())
         return;
      
      $ActivityModel = new ActivityModel();
      // Get five pending notifications.
      $Where = array(
          'NotifyUserID' => Gdn::Session()->UserID, 
          'Notified' => ActivityModel::SENT_PENDING);
      
      // If we're in the middle of a visit only get very recent notifications.
      $Where['DateUpdated >'] = Gdn_Format::ToDateTime(strtotime('-5 minutes'));
      
      $Activities = $ActivityModel->GetWhere($Where, 0, 5)->ResultArray();
      
      $ActivityIDs = ConsolidateArrayValuesByKey($Activities, 'ActivityID');
      $ActivityModel->SetNotified($ActivityIDs);
      
      foreach ($Activities as $Activity) {
         if ($Activity['Photo'])
            $UserPhoto = Anchor(
               Img($Activity['Photo'], array('class' => 'ProfilePhotoMedium')),
               $Activity['Url'],
               'Icon');
         else
            $UserPhoto = '';
         $Excerpt = Gdn_Format::Display($Activity['Story']);
         $ActivityClass = ' Activity-'.$Activity['ActivityType'];
         
         
         $Sender->InformMessage(
            $UserPhoto
            .Wrap($Activity['Headline'], 'div', array('class' => 'Title'))
            .Wrap($Excerpt, 'div', array('class' => 'Excerpt')),
            'Dismissable AutoDismiss'.$ActivityClass.($UserPhoto == '' ? '' : ' HasIcon')
         );
      }
   }