As I was doing research on a post-in-progress when I went Google and entered my search terms. The third or fourth organix search result was an article on Forbes.com. Upon clicking through on that link I was greeted with this wonderful Google ad unit.
I look forward to seeing this on more sites in the future because it makes so much sense for content aggregators, news sites, retail sites and content providers. Google in all of it's search majesty may not every time deliver you to the best content within the site you have selected so by providing visitors with access to being able to see all related content just within that site the visitor delivered by search is provided with the best possible chance of finding the right content quickly.
I would be interested in finding out what % of visitors interact with this unit and if it has reduced the bounce rate of search based visitors.