WordPress at a glance
filter is not described

add_ping filter-hook . WP 2.0.0

Filters the new ping URL to add for the given post.

Usage

add_filter( 'add_ping', 'filter_function_name_2973' );
function filter_function_name_2973( $new ){
	// filter...

	return $new;
}
$new(string)
New ping URL to add.

Where the hook is called

add_ping()
wp-includes/post.php 4281
$new = apply_filters( 'add_ping', $new );

Where the hook is used (in WP core)

Does not used.