Seriously not trying to troll, but could someone help explain where Google might see 3.2 billion dollars of value in a company that pretty much just sells a successful thermostat?
Each Nest will feed data (anonymized, of course /cough/) back to Google so they'll know home heating patterns, heck, home usage patterns (it watches activity and proactively & predictively adjusts for when people are/aren't around). Feed vast amounts of that data into the cumulatively large (no adjective does it justice) data mining process and they'll know that much more about [m|b]illions of people & locations.
US$3.2B? In the USA alone that works out to $0.003 per person per day over 10 years (assuming everyone has a Nest device in the long run; optimistic calculation, but sets the ballpark values).