Hacker News Reader

Really? I info-dump on my partner all the time about all sorts of specific products. She’s never mentioned one randomly pop up in an ad. I can honestly say I’ve performed your test thousands of times.

As a counter-experiment, try thinking of some product and intentionally DON'T search for it or say or type it anywhere. Make sure it's also not something you heard about recently from a friend or in the media. If you then see ads appear for that product you can be sure it's just baader-meinhof.

Talking with another person won't test whether they're correlating via IP or location.