it is amusing that you mentioned this because google's business strategy is to steadily erode the privacy of all human beings and monetize it at each step. they can try to dance around this all day with marketing and it doesn't matter.

it's only a matter of time before the glass hardware has an attachment that reads your mind so you exert even less effort than currently, e.g. blinking. google will then take that data and sell it to marketers, the USG, and whoever else they can, so everyone knows what you're going to think before you think it. google predictive thinking... so sad.