Google has a secret page with a list of all the things you've bought online

A secret feature has been discovered - and there is no easy way to turn it off. Photo / Getty Images

Remember that period in March 2013 when you were really into birds and bought that weird book about Madagascar birdlife? Or that "Fifty Shades of Grey" book purchase you made in the middle of the night? No? Well, Google does.

The internet giant has been recording all your purchases for years - and there is no easy way to turn the feature off.

Google scans Gmail and other sites to track everything you buy online and stores it all in a site dedicated to your purchases.

You can check your list of purchases on this link (you have to be logged into your Google account): https://myaccount.google.com/purchases.

Google pulls the receipts from your Gmail and compiles a detailed list of all your purchases.

The secret Google feature has now been discovered, just a week after Google CEO Sundar Pichai wrote in a New York Times op-ed that "privacy cannot be a luxury good".

Meanwhile, Google has spent the past few years mining your Gmail inbox for receipts on goods and services you've purchased.

"To help you easily view and keep track of your purchases, bookings and subscriptions in one place, we've created a private destination that can only be seen by you," a Google spokesperson told CNBC after the site unveiled the feature.

"You can delete this information at any time. We don't use any information from your Gmail messages to serve you ads, and that includes the email receipts and confirmations shown on the Purchase page."

Except, as CNBC reports, deleting these items off the list is not as simple as Google makes it sound.

There is currently no way you can do a mass delete of your purchase history in Gmail, and you can only delete transactions one by one (in many cases, we're talking years' worth of shopping).

You can, however, can keep future purchases from getting sorted into this page in your settings by choosing "do not use private results" in https://www.google.com/preferences.

Google told CNBC it doesn't use the information to show you ads and promises it "does not sell your personal information, which includes your Gmail and Google Account information" and does "not share your personal information with advertisers, unless you have asked us to".

However, it is unclear why the feature exists. Google says it does it for people's convenience but, as people are pointing out on social media, it is hardly convenient when it is basically a hidden feature that most people have never heard of.