gistfile1.php

<?php

// only allow a single post to be sticky
function post_published_notification( $ID, $post ) {
    global $_POST;
    if (array_key_exists('sticky', $_POST)) {
        update_option('sticky_posts', array() );
    }
}
add_action( 'publish_post', 'post_published_notification', 10, 2 );