But the powerful voice assistant may not be as innocent as you might think. The BBC's recent Panorama documentary on Amazon revealed how the company is collecting and analysing data on its users, and the Echo smart speakers are a key vehicle for that. 

Since being introduced in 2014, the Echo has exploded in popularity and a whole industry has grown up around it. Alexa is now built-in to well over 100,000 smart home products, and that number only looks set to grow.

Despite not having the same grounding in smartphone technology as the likes of Siri and the Google Assistant, it remains top dog in this burgeoning industry. Alexa has proven to be the go-to wake word for millions of people to answer questions, play music and control their smart home.

However, as you might be aware, every recent voice command is available to play back in the Alexa app, and it turns out the always-on Amazon Echo devices are busy collecting data at an alarming rate. 

Does Alexa always listen to me?

Amazon states on its website that Echo devices only record when they hear the wake word. It says that the device detects the wake word by identifying acoustic patterns that match the wake word. No audio is stored or sent to the cloud unless the device detects the wake word (or Alexa is activated by pressing a button).

All voice recordings streamed to the cloud are encrypted and securely stored on Amazon's servers. You can review and delete voice recordings at any time in the Alexa App, so you can find out what Alexa has recorded.

Some people dislike having any device with microphones in their home, and avoid any private conversations that could contain any sensitive information over fears that Alexa (and therefore Amazon employees) could potentially be listening to them.

The such fears are not completely unfounded. Indeed, one couple's conversation was recorded and sent to a random contact in 2018. Amazon apologised and said it was an "extremely rare occurence". 

Police in Florida even requested Amazon Echo recordings to help them solve a murder in 2019.

Cameras, such as the one on the Echo Show, present another method of potential surveillance.

How do I stop Alexa from listening to me?

You can press the physical button on your Amazon Echo to disable the microphones, and it's widely accepted this does stop Alexa from listening. If this was not the case, it would be a huge violation of users' trust.

Amazon took this a step further on recent Echo Show devices: there's a physical shutter which moves in front of the camera to block its view.

When the microphones are not disabled, Alexa is always listening out for the wake word - otherwise an Echo speaker wouldn't be nearly as useful as a hands-free device.

The Pure DiscovR (which has built-in Alexa) even offers an option to physically disable it by pushing the whole unit down.

You can go one step further with Paranoid, a company which specialises in protecting people's privacy when using technology. Its three products can physically intercept the microphones when the wake word isn't heard.

One example is the Home Wave, a device which physically attaches to the Amazon Echo and 'discreetly generates noise and interference in close proximity to the smart speaker's microphones to jam them'. By saying 'Paranoid' before you wake the smart speaker, the jamming will temporarily be stopped to ensure it can hear your command. See the full range of Paranoid products here

Of course, you could just unplug your Amazon Echo completely when not in use, but that somewhat defeats the point of having a convenient hands-free assistant. 

How dangerous is Alexa?

This all depends on your attitude to privacy. Many people accept that their data is being collected while using a smart speaker, but without carefully reading the privacy policy (and let's face it, no-one does) you might be unaware of what information is collected and how it is used. 

In the aforementioned Panorama programme, we learned that the company's approach has been to collect as much data on its customers as possible, building a comprehensive profile of each user. 

This data can then be used to tailor product recommendations on its site and in other Amazon services, such as Amazon Music. While you might have not given explicit consent for this to happen, agreeing to Amazon's terms and conditions means you have unwittingly given that permission. 

Amazon doesn't offer one place for you to see everything it knows about you. CNBC has outlined various places if you regularly use multiple Amazon services, including an Amazon Echo. The results may come as a shock to you, but that data is the foundation of upon which Amazon has built its success. And, if this is a shock, then know that plenty of other companies collect and use your data in a similar way.

If privacy is a top priority for you, we'd recommend setting Alexa to automatically delete voice recordings from time to time, and using the physical button to mute the microphones when speaking about sensitive information. 

Like many things, it's important to strike a balance. We feel you can make use of the many benefits of Amazon Echo devices, while taking the necessary precautions to ensure your private life remains private. 

We have an equivalent article on the Google Assistant: read Is Google Home listening to me?

Evaluated the concerns and still keen to buy one? Check out our guide to the best Amazon Echo.