Jetpack_Subscriptions_Widget::increment_subscriber_count PHP Method

    function increment_subscriber_count($current_subs_array = array())
    {
        $current_subs_array['value']++;
        set_transient('wpcom_subscribers_total', $current_subs_array, 3600);
        // try to cache the result for at least 1 hour
        return $current_subs_array;
    }