Open all external links in a blank tab

<script>
/*!
 * Automatically rel=nofollow external links and open them in a new tab
 * @author : @imperativeideas
 * @version: 1.0
 */

jQuery(function() {
    // Replace imperativeideas.com with your domain name!
    $('a[href^="http://"]').not('a[href*=imperativeideas]').attr({
        'target'    : '_blank',
        'rel'       : 'nofollow'
    });
});
</script>