We were taking a tour of a house for sale, and commented on the Haiku fan that they'd installed. (Amazing fans... they're "uneven" so they mimic the natural rise and fall of a breeze, rather than a steady stream of air.) For days afterward, no matter what we looked at online, there were ads for Haiku fans. All because our Android phones were active, in pocket or purse, while we were talking to the home owners, and that information was passed to Google Adsense.