For a long time it was considered a myth and dismissed by major technology companies.

But experts have revealed that eavesdropping on your conversations has become a multi-billion dollar industry.

Earlier this week, a leak from a leading marketing firm seemed to confirm how companies are using your smart device microphones to listen in and then sell the data to advertisers.

“You’re talking to one of your friends about a holiday in Portugal and then what do you see a day later or the same day? An ad for a trip,” data security expert Andy LoCascio told DailyMail.com.

The first slide of CMG’s leaked pitch deck describes how their active listening software listens to your conversations and extracts real-time intent data

Below we break down the process step by step, from identifying a “data trail” left by consumer conversations and online behavior to creating targeted digital ads.

Last week’s leak came from a pitch deck from CMG, a marketing partner of Facebook, Amazon and Google.

The deck – which was apparently created for prospective customers – described CMG’s “active listening” software, which collects data from people by listening in on their conversations.

According to LoCacio, the active listening software can be activated via any app on an Android or iPhone device, and other devices such as smart home assistants can also listen in.

In addition, these devices listen virtually all the time, not just when you intentionally use your microphone to make phone calls or talk to Alexa, for example.

“On most devices, there is no device state where the microphone is inactive. It is almost always active when Siri or another voice-activated assistant is present on the device,” LoCascio said.

Companies that want to collect and sell your voice data often gain access to your microphone through apps.

Typically, apps get permission to use your microphone through a clause “buried in the myriad permissions you accept when installing a new app,” he added.

This means that many users agree to the eavesdropping without being aware of it.

“The problem is that the form of consent is a Faustian pact based on the motto ‘all or nothing,’” says data protection expert and consultant Sharon Polsky.

“So many websites say, ‘We collect information from you and about you. By using our website, you agree to everything we do.’ You have no way to opt out,” she added.

LoCascio explained that CMG and other companies get away with it this way, even in states like California, where there are laws prohibiting the recording of phone conversations without a person’s knowledge.

“To be clear, there are no laws about this. If we give someone permission to use our device’s microphone and we click away all the other terms of use that none of us ever read, then of course they can use it,” LoCascio said.

This lack of protective laws has “created an entire data trading industry that is now worth billions,” Polsky said.

Google, Amazon and Facebook are specifically touted as CMG customers, but these tech giants have denied using CMG’s active listening software.

The rapid growth of this industry is partly due to the development of sophisticated large language models such as Chat GPT.

These extremely powerful AI tools have made it easier and faster for advertisers or other third parties to mine our voice data for valuable information, LoCascio noted.

“All I have to do is take one of these transcripts, paste it into the ChatGPT field and then ask a simple question. For example, ‘Please tell me what products and services I could offer someone based on this conversation,'” he explained.

Once the voice data is collected, it can be sold to advertisers to help guide and improve their targeted marketing, but it can also be sold to other clients who might use it for entirely different reasons.

“They could record these conversations for all sorts of purposes,” LoCascio said.

“It’s one thing to say they’re doing it for advertising, and they can say that, but they’re blindly selling that information to other people. And they’re not sanitizing it, so they’re basically selling an audio transcript,” he added.

Other examples of buyers of voice data include insurance companies that want to use it to create personalized insurance rates and the federal government, Polsky said.

“One of the buyers of our information – information about us – all of our opinions, our preferences, our connections, our travel routes – is the government,” she said.

And there are other insidious entities out there who are after our voice data, such as “people on the dark web who want to profit from defrauding us,” Polsky said.

That means sharing your Social Security information or other sensitive personal information could put you at risk of identity theft, LoCascio said.

CMG is an American media conglomerate based in Atlanta, Georgia. The company provides broadcast media, digital media, advertising and marketing services and had revenues of $22.1 billion in 2022.

CMG did not respond to DailyMail.com’s request for comment.

The leaked deck details the six-step process the company’s active listening software uses to collect consumer voice data seemingly through any device equipped with a microphone.

It is not clear from the slideshow whether the active listening software is listening continuously or only at certain times when the phone microphone is activated, for example during a call.

When asked whether lawmakers would take action to protect the public from this type of surveillance, LoCascio said it was highly unlikely and probably wouldn’t make a significant difference anyway.

“You can write as many laws as you want, but the bottom line is: we all release them from liability as soon as we click ‘Yes, I agree to your terms of service, whatever they are,'” he continued.

That’s why it’s important for device users to be aware of the privacy risks that come with simply reading an app’s terms and conditions and blindly accepting them.

To prevent your voice data from being collected and sold, LoCasio recommends going through all of your apps and deleting anything you don’t use regularly.

After you’ve reduced the number of apps you have, go through the ones that remain and carefully consider which apps you trust to access your microphone and which you don’t.

For those that don’t, change the settings to prevent access to your microphone. This should prevent them from potentially eavesdropping on your conversations.

And if you downloaded an app for a specific purpose and no longer need it, delete it, LoCascio said.

If you granted access to the microphone when downloading, if the program is left unused on your phone, it will have enough time to listen to your conversations at any time.

Polsky added that it is best to keep your phone and other devices turned off when not in use.

And ultimately, the most important thing is to be aware of the privacy risks associated with your own devices, she said.

“You can’t trust anyone these days,” LoCascio said.