When I downloaded a copy of my Facebook data last week, I did not expect much. My profile is sparse, I rarely post anything on the website and I rarely click on ads. (I'm what some call a Facebook "lurker.")
But when I opened my file, it was like opening the Pandora's box.
With a few clicks I learned that about 500 advertisers – of whom I had never heard, such as Bad Dad, a motorcycle parts store, and Space Jesus, an electronica band – had my contact information, which is my E Mail address, phone number and full name. Facebook also had my entire phonebook, including the number, to call my apartment number. The social network even had a permanent record of the approximately 1
There was so much that Facebook knew about me – more than I wanted to know. But after looking at the entirety of what the Silicon Valley company had received from me, I decided to better understand how and why my data was collected and stored. I also wanted to find out how many of my data can be deleted.
The way Facebook collects and treats personal information was the focus of attention in the middle of the week, when CEO Mark Zuckerberg answered congressional questions on privacy and on his responsibilities to users. During his testimony, Zuckerberg repeatedly said that Facebook has a data download tool that "allows people to see and extract all the information they've entered into Facebook."
That's an exaggeration. Most basic information, like my birthday, could not be deleted. More importantly, the data that I found offensive, like the list of people I did not make friends with, could not be removed from Facebook.
"They do not erase anything, and that's a general guideline," said Gabriel Weinberg, founder of DuckDuckGo, which offers Internet privacy tools. He added that data would be saved to help brands target ads.
Beth Gautier, a Facebook spokeswoman, put it this way: "If you delete something, we'll remove it so it's not visible or accessible on Facebook." added: "You can also delete your account at any time, it can take up to 90 days to delete all backups on our servers."
Browsing your Facebook files is an exercise that I can highly recommend if you Take care of how your personal information is stored and used. Here's what I've learned:
Facebook retains more than we think
When you download a copy of your Facebook data, you'll see a folder with multiple subfolders and files. The most important one is the "index" file, which is essentially a raw data set of your Facebook account, where you can, among other things, click through your profile, friends list, timeline and messages.
A surprising part of my The index file was a section called Contact Info. This contained the 764 names and telephone numbers of all persons in the address book of my iPhone. On closer inspection, it turned out that Facebook had saved my entire phone book because I uploaded it when I set up the Messenger Messenger Messenger app.
That was disturbing. I had hoped that Messenger would use my contact list to find others who also used the app, so I could easily connect to them – and keep the relevant contact information for only the people in Messenger. But Facebook kept the entire list, including the phone numbers for my car mechanic, home dome and pizzeria
This felt unnecessary, even though Facebook clings to your phone book to keep it in sync with your contact list on Messenger and to people who sign up for the messaging service again. I have decided to disable the sync and deleted all my phonebook entries.
My Facebook data also showed how little the social network forgets. For example, not only did I record the exact date of registering for Facebook in 2004, but also when I disabled Facebook in October 2010 to re-enable it four days later – something I hardly remember.
Facebook also kept a history of each time I opened Facebook in the last two years, including what device and web browser I used. On some days it even logged my locations, such as when I was in a hospital two years ago or visited Tokyo last year.
Facebook logs this data as a security measure to sign suspicious logins of unknown devices, much like banks send a fraud alert when their credit card number is used in a suspicious location. This practice seemed reasonable, so I did not try to clean up this information.
But what bothered me was the data that I had explicitly deleted but which remained in sight. On my friends list, Facebook had a record of "Distant Friends," a dossier of the 112 people I removed, along with the date I clicked on "Unfriend." Why should Facebook remember the people I have excluded from my life?
Facebook's statement was unsatisfactory. The company said it could use my list of deleted friends so that those people do not appear in my feed on the "On This Day" feature, which brings back memories from past years to help people reminisce , I would like to be able to finally delete the list of deleted friends.
The Advertising Industry Has Eyes Everywhere
What Facebook held to me is not as scary as the sheer number of advertisers who have my information in their databases. I found that out when I clicked on the Ads section of my Facebook file, which showed the last 12 ads while browsing the social network.
Below, there was a section titled "Advertisers Using Your Contact Info," followed by a list of about 500 brands I've never interacted with in the vast majority. Some brands sounded obscure and sketchy – they called it "Microphone Check," which turned out to be a radio broadcast. Other brands were more familiar, such as Victoria's Secret Pink, Good Eggs or AARP.
Facebook said unknown advertisers could appear on the list because they got my contact information from elsewhere and put it in a list of people and uploaded that list to Facebook. Brands can upload their customer lists to a tool called Custom Audiences, which they use to find the Facebook profiles of the same people who provide them with ads.
Brands can get your information in many different ways. These include:
• Purchasing information from a data provider, such as Acxiom, which has built one of the world's largest commercial databases of consumers. Last month, Facebook announced that it would limit advertisers' advertising to ads using third-party data brokers like Acxiom.
• Tracking technologies such as web cookies and invisible pixels that are loaded into your web browser to gather information about your browsing activity. Facebook offers 10 trackers to help brands gather their information, according to Ghostery, who offers privacy tools that block ads and trackers.
• Someone with whom you shared information might share it with another entity. For example, your credit card loyalty program could share your information with a hotel chain, and this chain of hotels could offer you ads on Facebook.