Was browsing the net the other day, and happened to stumble across this http://www.wisegeek.com/what-is-the-mystery-behind-the-mona-lisa.htm. That's not a standard adsense ad unit! How'd they do that???
Likely answer is that they are a premium publisher. They have a different set of rules to your average Adsense user.
Those are premium adsense publishers. Only highest-earning Adsense publishers may be eligible for dedicated account management through AdSense premier level service. Many of the publishers in this program are within the top 1% of Adsense earners, are among the largest 100 sites in their market, and include large brand names with content that generates highly competitive advertiser demand.
you need higher traffic to get that service or google will contact you to discuss some $$$ if you forget to apply on adsense,.. nice
Then why did you post? Just trying to be a dummy? But to answer the question, they look like a premium adsense publisher to me.