In order to improve your experience with Google products, Google Analytics is updating its data sharing policy. You now have the ability to share your Analytics data with other Google services. This will improve integration, enable additional features in Google's advertising services (including Google Analytics, AdWords and AdSense) and improve your experience with these products.
and the button to accept.
AdWords is already somewhat linked, but I didn't know they (could) use Analytics data for improving (?) AdSense optimization.
I wonder if it'd be for the better or for the worse if they 'saw'... uh... no, I mean 'used' what's in there.