Even then, a lot of the "I was talking about something with a friend and never even Googled it then got an ad for it" can be explained by Facebook leveraging th

Even then, a lot of the "I was talking about something with a friend and never even Googled it then got an ad for it" can be explained by Facebook leveraging their social graph to target ads if your friend googled something. They have a social graph that indicates who your probable friends are, regardless of actual Facebook/Instagram/Whatsapp friend status; using Bluetooth & Wifi identifiers based on physical closeness.