If I review, say
Toptenlisted.com - The Premier Source for Original Top Ten Lists, the review plus the link to the website appears in my SU blog at interfaceleader.stumbleupon.com
It has a nofollow tag, so Google and Wordpress won't count it, but people can still use it as a link - I've had quite a few people come to my site via links from people's individual stumble blogs, rather than by stumbling directly.