Get related posts by tag in WordPress

gistfile1.php

<?php
//for use in the loop, list 5 post titles related to first tag on current post
$tags = wp_get_post_tags($post->ID);
$tag_in = array();
foreach($tags as $tag):
setup_postdata($tag);
$tag_in[] = $tag->slug;
endforeach;
$the_tags = implode(",", $tag_in); //Create
 
if ($tags) { ?>
<?php
//$first_tag = $tags[0]->term_id;
//tag_slug__and
$args=array(
'tag' => $the_tags,
'post__not_in' => array($post->ID),
'posts_per_page'=>5,
'caller_get_posts'=>1,
'post_status' => 'publish',
'orderby' => 'rand',
'order' => 'DESC',
);
$my_query = new WP_Query($args);
if( $my_query->have_posts() ) {?>
<section>
<h3>Related Posts</h3>
<div>
<ul>
<?php
while ($my_query->have_posts()) : $my_query->the_post(); ?>
<li><h4><a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title_attribute(); ?>"><?php the_title(); ?></a></h4><p><?php the_time('F j, Y'); ?></p></li>
 
<?php
endwhile;
}
echo '</ul></div></section>';
}
wp_reset_query(); ?>