Most of us use Google on a day-to-day basis, but how much does it know about us as a result?
Dylan Curran is a web developer who has looked into this, and has started a Twitter thread on the amount of information Google stores about its users.
Want to freak yourself out? I'm gonna show just how much of your information the likes of Facebook and Google store about you without you even realising it
— Dylan Curran (@iamdylancurran) March 24, 2018
One thing you may not be aware of is the level of detail Google can store about your exact location.
"Every time you turn on your phone and your location is turned on, Google will pinpoint where you are and at what time," Dylan explains. "Then if you travel to another destination it will map out how long it took you to get there."
It also logs your search history, even if you think you've deleted it, because "they store it in a database that's not directly tied to your browser."
"You have to go in and delete separately, and you have to do this on every individual device that you browse from."
Using incognito mode doesn't make any difference either: "If you think you're browsing privately, it's still in the database."
Dylan says the vast majority of people don't have any idea that this is going on - and, alarmingly, it's easier than you might think for someone else to gain access to this information.
"If someone gets the password to your account, whether it's a close friend, a parent or even an external hacker, they can download a chronological diary of your life for the last ten years."
Dylan only discovered all of this when he received an email from Google with his own archive. In it, he found his entire search history along with every file he has ever downloaded, all the YouTube videos he has watched, all of his emails (including deleted ones), every app he has ever installed and ads he has viewed or clicked on.
He also found all of the Google Calendar events he has stored or attended in the last year, "and it actually confirmed whether I attended or not, even though I've never clicked attend."
"I was a little bit disturbed."
If you want access to your archive, you can go to google.com/takeout and request to download it. Under EU law, companies are obliged to give your information back to you if you request it, but as Dylan says, they don't make it very clear that you can do this.
To find out more, see Dylan's Twitter thread here.