/**
  * @return bool True if user should see unread data in this forum
  */
 function can_mark_read($userid = 0)
 {
     global $CFG, $USER;
     $user = forum_utils::get_user($userid);
     return $this->can_view_discussions($userid) && $CFG->forumng_trackreadposts && !isguestuser($user);
 }