Nest is governed by Google's catch-all privacy policy. So the data they upload to the cloud can be used across the entire Google ecosystem. If you're using Goog

Nest is governed by Google's catch-all privacy policy. So the data they upload to the cloud can be used across the entire Google ecosystem. If you're using Google Photos, they already have tremendous amount of data on you, so this isn't anything particularly new. This will, however, enable a new ad-targeting method where they can ensure the ads delivered are specific to the individual using an otherwise shared device. Additionally, this "feature" can be combined with the always listening capabilities of Google spyware to definitively link your audio profile to your facial profile. This will enable Google to build an index of voice fingerprints, with facial profiles that can be used in the future in some capacity... like being able to isolate your voice in a room, once a camera detects your face, or vice versa. This all can be spun as an "improved product experience". edit- there's no need to send video or an image to Google everytime, if there's a unique identifier mapped to your facial data. Only that will need to be sent up to Google and the statement you have quoted would technically be correct.