WP advertising ID

The first thing I realized while watching the video demonstrating the setup process of Cortana, was that there appears to be a new setting titled Advertising ID, that doesn't currently exist on my Lumia 720. Do we have any more information about it? Looks like Microsoft is about to take advantage the information you give Cortana. Apparently you can also turn it off.

2e1wqqh_medium

via i60.tinypic.com