connected devices
So if your phone geolocates to the frozen north, and the thermostat indicates the furnace is working extra hard, expect to see warm vacation destination ads in your desktop web browser at work, or something like that.
Further people keep repeatedly claiming that the Nest device has some sort of presence detection. To my knowledge it has no such thing -- it simply allows you to program it by daily overrides instead of actively turning it on or off. Though of course many people eventually just end up setting it to a static temperature.
There is no amazing in-house intelligence gathering platform here.
How does this work then?
"Auto-Away saves energy by reducing heating and cooling in empty homes. Instead of having to turn the thermostat down every time you leave the house (and back up when you return), the Nest Learning Thermostat turns itself down automatically when it senses that you’re away."
"Activity sensors
Nest’s activity sensors have a 150° wide-angle view. That range enables Nest to activate Auto-Away in 90% of homes."
Don't know if its just a 0-D light level sensor or a PIR motion detector or a camera. But it does have a 150 degree FoV which vaguely implied optics.
It has certain architectural implications, my thermostat is on a lightly traveled inside hallway between sleeping and living quarters, so I'll never be able to use a nest; it would consider the house unoccupied pretty much all the time other than bedtime and wakeup time. I guess there are people with thermostats installed in their kitchen and/or living room and/or home office?
Nest is in a unique position as basically the only player out of many who have successfully made home automation devices that people actually want, and don't look like they came out of a backyard plastic mould cast in the late 60s.
Search around for home automation solutions - the hardware is universally clunky, the software atrocious. Only the most dedicated of DIY geeks need apply (or people who can pay contractors to make the ugliness go away).