Zivush - 4:19 am on Aug 6, 2012 (gmt 0)
I have seen these keywords links in one of my toughest competitor site - [the well known about ..etc].
When clicked you are taken to the site's search page, which is actually "Results by Google Custom Search".
To my best knowledge, unless a redirect trick is implemented, this is a kind of feature given to premium Adsense publishers because the url looks real - example.com/lr/popular-keyword/1288309/4/
I haven't seen these type of pages on organic results, but if they are (as expressed here), it is an unfair benefit given to this site no matter how authoritative it is.