What Facebook knows about me and you

The recent Cambridge Analytica “scandal” has triggered conversations on how Facebook(FB) tracks our lives and drives the public opinion.

But what FB knows about you and me? Dylan McKay reports on Twitter that FB keeps data on his calls and other weird stuff. I decided to have a look on what FB has on me.

You can actually download “all” the data FB has about you by following the steps bellow:

  1. Click on the down arrow at the top-right of any Facebook page and select Settings.
  2. Click on the “Download a copy of your Facebook data.” link at the bottom of the General section.
  3. Click on the “Download Archive” button and provide your credentials.

A download link will be emailed to you in a couple of hours.

So, I received the download link and started the download process.


My first surprise was the amount of data Facebook stores about me. I’m on FB since 2007 but 3GB of data seems a lot, given that I do not have much media (photos/videos) on my profile. I somehow feel important!

Ok. Now I have “all” my data locally on my machine. As seen in the screenshot most of this data is messages. All of my private or group conversations along with the files I exchanged (videos, photos, stickers etc) are stored in the messages folder.
The downloaded zip has an index.htm file I can open on my browser and start exploring.
The information is organized in eleven categories.


Your profile information. This is generally information you have willingly provided. Don’t complain.

Contact Info

Interestingly here are listed all your contacts, with phone numbers and emails. Even contacts that do not have FB or are not your friends on FB. The Facebook apps on your mobile asked you for permission to access your contacts once, remember? I understand that FB might use this information to suggest friends or perform similar functions. But for this purpose this information does not need to leave your device, be stored on FB servers and probably shared with third parties.
As I scroll down things get even more weird there are sections with your Call History and your SMS/MMS History. I really don’t get why this information is tracked and why it is stored on FB servers. Call and messaging history with Numbers, Names, Date/Time, Duration,… everything! Some screenshots follow.




Nothing interesting in these three categories. I guess we all know what we are sharing.


All your friends, friend requests (accepted and declined), removed friends, followees.
A weird category label is also here called “Friend Peer Group“. Mine has the value “Established Adult Life”. I guess it’s a category FB thinks you bellong in order to better serve you with ads.


All of your private or group conversations along with the files exchanged.


All the events you have attended or expressed interest.


Security stuff like your active sessions, account activity (logins, logouts etc) and ALL the IP Addresses you have used to access FB.


The information in this section has three subcategories

  • Ads Topics: Topic FB think you are interested so it can server you “better” and more targetted Ads
  • Ads History: History of Ads you have Clicked on
  • Advertisers with your contact info: Companies that have access to (part) of your data. Mine includes a list of about 200 companies. Some of them are well known companies, some we may hear in the next “data scandal”.


All the FB Applications you are using and have access to your profile and (some) data.


To sumarize, most of the collected information is somehow expected to be there. What is not expected is the Phone Call log and the SMS history. I feel that FB will have to provide more information on this and probably an apology sooner or later.

What is also weird is that I did not find much on location information (other than IPs) in the zip file. I’m sure that FB tracks location to provide more targeted campaigns. This makes me sceptical on how complete the dataset provided is.

All the above is not a product of scientific analysis. I just downloaded the zip file from FB and inspected what was there. I feel that with some more effort and data analysis tools more information can be extracted from the provided zip file.

Update 2018/03/25: An article of ArsTechnica on the subject that includes some official FB responses

Update 2018/03/26: According to Facebook, your contacts are used for its friend recommendation algorithm. And if you agreed to allow Facebook to access your contacts list prior to Android 4.1, you were giving the company permission to see your call and text logs by default. This practice was eventually eliminated with version 16 of the Android API, although Facebook could still access phone and SMS records by citing an earlier Android SDK version. The tracking of calls appears to have ended in late 2017. [via PhoneArena]

Update 2018/03/26: Facebook Use of Sensitive Data for Advertising in Europe [PDF]