This information may seem mundane compared with smartphone geolocation software that follows you around or the trove of personal data Facebook Inc. vacuums up based on your activity. But even gadgets as simple as light bulbs could enable tech companies to fill in blanks about their customers and use the data for marketing purposes. Having already amassed a digital record of activity in public spaces, critics say, tech companies are now bent on establishing a beachhead in the home.

“You can learn the behaviors of a household based on their patterns,” says Brad Russell, who tracks smart home products for researcher Parks Associates Inc. “One of the most foundational things is occupancy. There’s a lot they could do with that.”

From the article "Your Smart Light Can Tell Amazon and Google When You Go to Bed" by Matt Day.