Some "smart TV"'s can phone home with TV usage data. I wouldn't be too surprised if there was a shazzam like thing in some smart TV's that can detect certain a

Some "smart TV"'s can phone home with TV usage data. I wouldn't be too surprised if there was a shazzam like thing in some smart TV's that can detect certain advertisements. eg - https://www.cnet.com/how-to/disable-vizio-smart-tv-spying/ https://www.cnet.com/how-to/disable-vizio-smart-tv-spying/ Once you match the public IP address of all your devices you can link up the identities and do fun advertising stuff.