googlewebmaster.php

// auto insert hidden hatom data in single posts
add_filter('the_content', 'hatom_data_in_content', 100);
function hatom_data_in_content($content) {
	if (is_single()) $content .= get_hatom_data();
	return $content;
}

// returns hidden hatom data for current post
function get_hatom_data() {
    $html = '<div class="hatom-extra" style="display:none;visibility:hidden;">';
    $html .= '<span class="entry-title">'.get_the_title().'</span>';
    $html .= '<span class="updated"> '.get_the_modified_time('F jS, Y').'</span>';
    $html .= '<span class="author vcard"><span class="fn">'.get_the_author().'</span></span></div>';
    return $html;
}