It’s an oft-repeated tale: Someone talks with a friend about a certain thing, and then, bang, an ad for it appears on the smartphone screen.

Some cases are easy to explain. A colleague of mine who was about to get married claims that she never googled wedding dresses, yet the pesky search engine started suggesting them all the same. And then, three months after the wedding, products for newborns began appearing in her search results, although she was not even planning to have children. There’s no great mystery here, we can dispense with the conspiracy theories.

But some cases arouse more suspicion. For example, you’ve never had a barbecue before, one day you voice the idea, and, all of a sudden, you see an ad for barbecue equipment. Coincidence?

After hearing such stories, or experiencing them personally, many people become convinced that the Internet giants are all listening to us through smartphone microphones. Fact or fiction?

There are several explanations for how the search giants sometimes hit a bull’s-eye, that doesn’t involve conspiracy theories about eavesdropping through the microphone.

Explanation 1: Internet services build accurate models

In the article “Your phone isn’t really spying on your conversations — the truth might be even creepier,” a former Google employee says that Google and Facebook essentially have a digital avatar of you that tries to replicate your behavior with the aid of machine-learning methods. At some point, your digital stand-in becomes so much like you that it begins to predict what you want.

About Facebook, I heard it can determine whether a woman is pregnant even before she herself knows — by the rate she scrolls through the social network’s feed.

Personally, I’m disinclined to believe in such telepathic abilities, but there is definitely some truth to this one.

Explanation 2: Accidental activation of the voice assistant

Another explanation for the search giants’ omniscience is the random activation of voice assistants. Sometimes, the phone thinks you said “Alexa,” “Ok Google,” “Hey Siri,” or “Cortana,” when in fact you didn’t.

It’s not necessary to pronounce these trigger words properly. Something similar is likely to produce the same effect and turn on the assistant — after which the phone really does listen in on everything, and then starts making relevant suggestions.

Explanation 3: User domains

Let’s say you talked with your friend or spouse about deodorant or the need for some (hopefully not), after which you did not start searching for it. But they did. If you see an ad for deodorant after the conversation, don’t be too surprised.

The thing is that the Internet service already suspects that your two accounts are somehow linked if you often hang out in the same place, perhaps on the same Wi-Fi network, maybe even take turns logging in to the same device. Such users may get put into “domains” by search engines, whereupon they’re shown some of the same products because they may make purchasing decisions together.

Explanation 4: Lucky guesses

I often see advertising that doesn’t match my interests: sauna equipment, pregnancy tests, trips to wherever — you name it. You’ve probably seen similar stuff.

But many people use search engines, so it’s possible that a random ad blitz might one day catch you after you’ve been talking to a friend about the benefits of saunas. And then you post online that your phone is spying on you. Meanwhile, folks who saw the same ad, but didn’t discuss saunas, write nothing. One story is seen, and the other one is never even told.

Conclusion

Here’s a yarn to wrap things up. A buddy of mine complained to colleagues that spoons were always going missing from the office kitchen. They decided to play a joke on him by ending all work e-mails to him with the words “spoons spoons spoons spoons” in white font. The mail client was Gmail. What happened? The poor guy started seeing ads for nothing but spoons. That looked pretty suspicious.

So, don’t just believe the rumors, get involved, do some experiment and see for yourself!

This article is written by Alexey Malanov, a malware expert with Kaspersky. (portions of the article was edited to fit into the post)