Wpsnipp – Submit to Stumbleupon.Adding this snippet to your wordpress themes loop located within the single.php or index.php will allow users to click this link and submit your post to Stumbleupon.In your regular browsing experience, you might find a site that you think would interest other people. The “thumbs up” icon works for all sites, and that is how new sites get into the database of StumbleUpon pages that are served to the end user during their stumbling session.
<a href="http://www.stumbleupon.com/submit?url=<?php the_permalink(); ?>&title=
<?php the_title(); ?>" rel="nofollow" title="vote up - <?php the_title(); ?>"
target="_blank">Submit to Stumbleupon</a>