Google AdSense team have sent out emails to the publishers announcing some changes how google can contact the publishers. This include five new categories of the preferences. A screenshot of the email is shown below.

So in a way google is offering some market based resaerch, special offers and help to the adsense publishers.
In order to activate the above options one have to either click the Go to Contact Prefrences link on the adsense welcome page after signin or to visit the My Account Tab in your adsense account.