Anecdote: I'm having dinner last night with a couple at their house and I'm advising one of them about getting an appliance for her partner - so we browse some

Anecdote: I'm having dinner last night with a couple at their house and I'm advising one of them about getting an appliance for her partner - so we browse some options on her cellphone together and find something suitable. Perhaps 30 minutes later, her partner was on his cellphone and gets an ad for the same appliance, he let us know because it was something he had been wanting. They were both on the same IP address via the router. While they initially had a good laugh, it was supposed to be a surprise. It really did annoy me and when I explained what was happening they found it equally amusing and frightening. I am pretty sure both of them went to bed that night worried that the other was going to be getting ads for things they might be looking at on the internet.