I've heard about this theory before and even saw where a few facebook friends had posted about some very strange coincidences. The odd part was that the ads suddenly popped up related to things mentioned in in-person conversations, NOT conversations done thru their phones...and as these were not common everyday items it made them all the more suspicious.
Well, a couple of days ago on my way home I stopped at an estate sale I saw. I looked at a lot of items and wound up buying a metal shelving unit and one of those long orange extension cords.
So I get home and want to sit back and chill for a bit. I turn on my phone and go to the facebook marketplace as I was looking at something there earlier...and it was NOT shelving units or extension cords. I had NO plans to buy either item, they were just something I ran across that had a really good price that I knew I could put to use.
I refresh the page and what are the first two ads I see? The first was for metal shelving units and the second was for orange extensions cords! I don't think I'd even ever seen ads for them before and I certainly never did searches for them before either.
So how could that happen? Wayyy too coincidental! Its looking very credible that they are indeed eavesdropping even when your off your phone.
Of course facebook denies it:
https://www.theverge.com/2016/6/3/11...rophone-denial