_you_ are prohibited, but Google is not. I'd suspect they will mix in more and more of this context (from Nest, from emails you provide, from your driving habits on Google Maps) to make ads "more personal" as time goes on.
Presumably Google could already be doing this in their own ads before this announcement. I don't know if this announcement implies any nefarious motives in this space (not to say they aren't planning this, but just seems unrelated).
