In a series of tweets, one IT expert has laid out exactly what the search giant knows about him, dating back to 2008, which he describes as ‘preposterous’.
It ranges from every place he visited in the past year to every website he clicked on, and even contained files deleted from his Google Drive cloud storage account.
The news comes in the wake of the Cambridge Analytica scandal, which saw a Trump-affiliated firm obtaining data on 50 million unsuspecting Facebook users.
This information was used to target voters in the US, based on psychological profiling, with political adverts spreading disinformation.
Web developer Dylan Curran, based in Waterford, Ireland, decided to download both his Facebook and Google archives on Saturday.
The data held by the world’s most popular social media site was fairly large, at around 600mb, equivalent to roughly 400,000 Word documents.
But this paled in comparison to Google’s data file, which was 5.5gb, almost ten times larger. This is around the same size as three million Word documents.
Sharing his findings on Twitter, in a post retweed more than 150,000 times, he said: ‘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.’
Mr Curran found that Google was constantly tracking his location in the background, including how long it took to travel between various points.
It also held details about his hobbies and interests, as well as guesses on his possible weight and income.
Speaking to NBC News, he said: ‘It’s wrong to trust any entity that big with so much information.
‘They’re just trying to make money,’ and at some point, ‘someone is going to make a mistake.’
Where you’ve been
If you have location tracking turned on via your smartphone, tablet or other connected device and they’re switched on, Google stores details of everywhere you’ve been.
For Mr Curran, this included his travels around Ireland over the previous 12 months, including journey times between towns and cities.
When MailOnline decided to drill down into this data, it revealed a surprising level of detail.
As well as foreign travel, it included the name of a number of pubs visited, the length of time spent in them, and the route taken to get home.
To find out what data Google stores on your travels, click here.
Events you’ve attended
Google’s data files contain a complete record of your Google Calendar.
This is broken down into all the events you’ve ever added, whether you actually attended them, based on your location, and what time you attended.
Mr Curran shared a section that shows him going for an interview for a job in marketing, including the time he arrived.
To access your Calendar history, as well as your complete Google data file, you need to request your Google Takeout file by clicking here.
Be aware that, if your file is anything like Mr Curran’s, this may take a long time to download.
Everything you’ve ever searched for
Google, somewhat unsurprisingly for a search engine, records everything you search for on the internet.
What might shock you, however, is that this is kept on file even when you delete your history.
Mr Curran’s log contained 90,000 different entries, even showing images he downloaded and websites he accessed.
This included banned torrent site ThePirateBay, which he mentions in his tweets to illustrate how much damage this information could do if it becomes public.
Google stores search history across all your devices on a separate database.
That means, even if you delete your search history and phone history, the search giant still has your entire history.
To delete it permanently, you have to manually access the My Activity log here and delete everything.
This will need to be done for all devices individually.
Ad topics that might interest you
Google builds a marketing profile on you, based on a number of factors.
These include details like your location, gender and age.
It also includes your hobbies and both your personal and professional interests, as revealed through your searches and web activity.
In the case of Mr Curran, this also included guesses about his relationship status, weight and income.
When MailOnline checked this, we found a range of interests, some of which seem to have been logged by a single search or website interaction alone.
To access your ad profile, click here.
Information you deleted and emails you sent
The Google Takeout file also includes a record of all of the information you’ve uploaded to your Google Drive account.
In Mr Curran’s, he found files he had already deleted, including past resumes and monthly budgets.
He also found all the computer coding files and websites he’d ever made, as well as his PGP private encryption key, which had been deleted, used to protect his e-mails.
Every e-mail Mr Curran ever sent or received, including deleted and spam messages, was also recorded.
To find out what files Google has from your Drive account and email, download your Takeout file here.
The apps you’ve used
Google holds information on all the apps and browser extensions you use.
This includes how often you use them, where you use them, and who you interact with through them.
This can include details like who you talk to on Facebook, what countries they are in and even when you go to sleep.
To find out what information Google has on the apps you use, click here.
Your YouTube history
Google knows all of your YouTube browsing history.
This can reveal a multitude of personal details about you, ranging from your political and religious beliefs, to mental and physical health issues.
In Mr Curran’s case, it revealed every YouTube video he’d ever searched for or viewed, since 2008.
To check your YouTube history file, click here.
When you worked out
If you use Google Fit, the firm also keeps records on every time you workout.
In Mr Curran’s case, this included all the steps he’d ever taken, every time he’d walked anywhere, as well as running and cycling.
It also included all the times he’d recorded meditation and yoga sessions.
Mr Curran has since deleted this information and revoked Google Fit’s permissions.
If you use Google Fit, download your Takeout file to access your records here.
All of the photos you’ve ever taken or searched for
Mr Curran’s Takeout file includes details of all of the photos he’s ever taken with his phone.
This was broken down by year and includes metadata on when and where he captured the images.
It also included every picture he’d ever searched for or saved.
This included every location he’s ever searched for or clicked on, every news article he’s ever searched for or read, and every google search he’d made since 2009.
To check your image history, download your Takeout file here.