Triggers after a notification is added for the user.
~~~
<?php
function my_component_init(){
ossn_register_callback(''notification', 'add', 'my_component_cb');
}
function my_component_cb($callback, $type, array $params){
//$params[owner_guid, type, poster_guid, item_guid, subject_guid]
}
ossn_register_callback('ossn', 'init', 'my_component_init');
~~~