I doubt that my IP address is a globally unique identifier. I can think of 15-20 devices that are sharing it now. Advertising networks jump through a lot of hoo

I doubt that my IP address is a globally unique identifier. I can think of 15-20 devices that are sharing it now. Advertising networks jump through a lot of hoops to tie those devices together in a small cluster of user profiles. How does the installation ID identify a person?