Earlier quoted context omitted.
I’m always puzzled by the need people have to try to dispel the notion that Facebook listens to ambient audio or conversations. They are the bad guys. They didn’t need to steal Android phone logs either, but they did.
I just wish there was a way to figure out _why_ I'm getting some ads, to dispel that fear. On Instagram last weekend I and a friend were shown a number of ads for Chandon sparking wine after I bought a bottle, and someone else at the party also did and we talked about it. Both of us insist we didn't google sparkling wine, Chandon, or anything we think relevant... it really does on the face of it appear Facebook had l…
You may have brought it online in which case almost certainly there was a FB tracking pixel fired back from the e-commerce website to signal that you did. On the other hand if you bought from an offline store and swiped a loyalty card while doing so, your transaction might have been uploaded to create a custom audience. If you paid by your phone or have your loyalty app on your phone this becomes even easier - convenient offline to online matching is the only reason loyalty program apps are pushed.
Finally, even if you didn't do any if these and the other person did, if you both connected to the WiFi at the party and checked FB (or better still you added the other person as a friend), the shared IP address between your devices is enough of a signal to begin connectings.