This recycling bin is following you - Quartz

Coming soon: an app that disables smartphone Wi-Fi if you're not within range of a known Wi-Fi source

"Recycling bins in the City of London are monitoring the phones of passers-by, so advertisers can target messages at people whom the bins recognize.
Renew, the startup behind the scheme, installed 100 recycling bins with digital screens around London before the 2012 Olympics. Advertisers can buy space on the internet-connected bins, and the city gets 5% of the airtime to display public information. More recently, though, Renew outfitted a dozen of the bins with gadgets that track smartphones."

This recycling bin is following you - Quartz