LONDON • An opinion piece in The Guardian newspaper reveals the many ways in which Internet titans Google and Facebook keep track of you.

GOOGLE KNOWS WHERE YOU'VE BEEN

The site stores your location if you have location tracking turned on every time you turn on your phone.

GOOGLE KNOWS EVERYTHING YOU'VE EVER SEARCHED - AND DELETED

Google stores search history across multiple devices, so even if you delete your search and phone history on one device, the data may be saved on others.

GOOGLE HAS AN ADVERTISEMENT PROFILE OF YOU

The site creates an advertisement profile of you based on information such as location, gender, age, hobbies, career, interests, relationship status, possible weight and income.

GOOGLE KNOWS ALL THE APPS YOU USE

The company stores information on every app and extension you use and knows how often you use them, where you use them and who you use them to interact with. Consequently, they know who you talk to on Facebook, what countries you are speaking with and what time you go to sleep.

GOOGLE HAS ALL OF YOUR YOUTUBE HISTORY

Google stores all of your Youtube history, so they probably know whether you're going to be a parent soon, if you're a conservative, if you're Jewish, Christian or Muslim and if you're feeling suicidal or depressed, among other things.

THE DATA GOOGLE HAS ON YOU CAN FILL MILLIONS OF WORD DOCUMENTS

Google offers an option to download all of the data stored about you. For Mr Dylan Curran, a data consultant and web developer who wrote the Opinion piece for The Guardian, the file size was 5.5 gigabytes, approximately the equivalent of three million Microsoft Word documents. It includes bookmarks, e-mail, contacts, Google Drive files, Youtube videos, photos, and businesses you bought from, besides your calendar, Google Hangout history, the music you listen to, how many steps you walk in a day, and other data.

FACEBOOK HAS REAMS OF DATA ON YOU, TOO

Facebook also offers an option to download all your data. For Mr Curran, the file was roughly 600 megabytes, about the size of 400,000 Word documents, and included every audio or text message sent or received, and all the contacts in his phone. Even chat stickers and where he logged in from were saved.

THEY CAN ACCESS YOUR WEBCAM AND MICROPHONE

The data collected by the companies includes tracking where you are, what applications you have installed, when you use them and what you use them for. They can access your webcam and microphone at any time too.

NEFARIOUS USES

According to The Guardian opinion piece by Mr Curran, the information has millions of nefarious uses. And if you manage to gain access to someone's Google account, you would have a chronological diary of everything that person has done for the last 10 years. For example, someone suspicious of the activities of his wife could look up her location and search history for the last 10 years.