A site that is built for Google AdSense that has no PR is showing up in the back link count for a site.
The first part of the page is a H1 tag with a KW rich phrases. The second part is ads by Google. The third part is paragraph of text about the subject. The last part is links to more google ads - when clicked a page of Google ads is displayed.
The site it is giving a back link to is not hard coded into the page. So I can only assume that when google crawled it they saw the google ads and counted them as back links.
I would be happy to PM the URL to anyone that wants to take a look.