Here is some PHP code you can use in wordpress to get the tags of your post ID.
[source:css]
$tags = wp_get_post_tags( $post->ID );
[/source]

Let’s assume the result is one category (264) and one tag (41).

1. If you are not using WordPress Mu, you can simply select from wp_term_relationships and wp_posts
2. If you are using WordPress Mu, you will need to specify the tables as wp_MU-BLOG-ID#_term_relationships and wp_MU-BLOG-ID#_posts. Let’s assume we are using WordPress Mu and our blog ID is 1. The tables we are working with are wp_1_term_relationships and wp_1_posts

[source:css]SELECT p.ID, COUNT(tr.object_id) AS cnt
FROM wp_1_term_relationships AS tr, wp_1_posts AS p
WHERE tr.object_id = p.id AND tr.term_taxonomy_id IN(264,41) AND p.id!=3987 AND p.post_status=’publish’
GROUP BY tr.object_id ORDER BY cnt DESC, p.post_date_gmt DESC LIMIT 5;[/source]

Notice that we have limited our results to the 5 most relevant posts. It is recommended that you limit this query because it can be a difficult query to process if you are running it on a blog that has thousands of posts. You can change LIMIT 5 to LIMIT 25 or so on blogs that are hosting less than 5,000 posts without seeing much of a difference in performance. On larger, more frequently updated blogs or WordPress MU sites which are hosting a lot of blogs on the same server, it is recommended that you cache the results of this query and only use it once an hour or once every time a blog entry has been updated.

I just made one php file called addthis_button.php that had this code in it:

[source:php]<?php
// change this to your addthis user name
$addthis_user=’asherbond’;
?>

<!– AddThis Button BEGIN –>
<script type=”text/javascript”>addthis_pub = ‘<?php print $addthis_user; ?>’;</script>
<a href=”http://www.addthis.com/bookmark.php?pub=<?php print $addthis_user; ?>&url=”<?php print get_permalink(); ?>”&title=”<?php print get_the_title($id); ?>”\”" onmouseover=”return addthis_open(this, ”, ‘<?php print get_permalink(); ?>’, ‘<?php print get_the_title($id); ?>’)” onmouseout=”addthis_close()” onclick=”return addthis_sendto()”><img src=”http://s9.addthis.com/button1-share.gif” width=”125″ height=”16″ border=”0″ alt=”" /></a><script type=”text/javascript” src=”http://s7.addthis.com/js/152/addthis_widget.js”></script>
<!– AddThis Button END –>
[/source]

Then I added the code to include it in each of these files: single.php, index.php, and archive.php:

[source:php] <?php include(‘addthis_button.php’); ?>[/source]