Google have patented a couple interesting patents that you would hate if you value your privacy …
Privacy-aware personalized content for the smart home
In simple words a home scanning system.
In one embodiment, a computing system may operate within a local area network. The computing system may include a network interface configured to receive a set of content items from a content server located remotely from the computing system and the local area network, a storage element for storing the set of content items, and a processor. The processor may be configured to determine first data relating to people, objects, or some combination thereof, select at least one content item from the set of content items based at least in part on the first data relating to people, objects, or some combination thereof without communicating the first data to the content server or any other computing device outside of the local area network, and communicate the selected at least one content item to a user of the computing system.