Facebook hasn't had a good week, ever since the social media giant got caught up in the data privacy scandal linked with data analytics firm Cambridge Analytica (CA). Just to recap, CA allegedly procured personal user data on over 50 million Facebook users, and this data was used for social media targeting in political campaigns. Since the scandal came to light, users have been looking for ways to remove their data from the social media website prompting the #DeleteFacebook online campaign. Part of that process, would include downloading all your data from the social network, so that you can retain your information even after deleting your account. Several people have been doing so in the recent past, and, there were some interesting revelations to be found within the data - including which advertisers have access to your data, as well as complete call records in some cases.
A tweet thread by software developer Dylan McKay suggests an interesting revelation wherein Facebook has access to call history details of McKay's conversations with his partner's mother. Add to that, Facebook seems to have historical records of all contacts (even those deleted), metadata of text messages, and metadata of cellular call logs. Notably, he was using an Android phone during November 2016 and July 2017 when the data breach seems to have occurred.
To view the history of your Facebook account's data, log in to Facebook.com on the desktop browser, click on the drop down icon on the top right of the page and select Settings. In the General tab, you will see the Download a copy of your Facebook data option. Clicking that will prompt you to re-enter your Facebook password; now select Start My Archive to initiate the download request. An email containing a ZIP file will then be sent to your registered email address. File size can depend on the activity frequency and age of your Facebook profile. In our case, the size was a massive 4.29GB.
Talking about advertisers extracting data from your Facebook profile, the ZIP file was spotted to contain an HTML folder by The News Minute, which has a page titled Ads. Here, you can find the list of "Advertisers with your contact info" buried at the end of the HTML page. The page also contains an "Ad Topics" section which includes the list of keywords that are used by third-party advertisers to potentially target ads on your timeline. Another interesting section in the file is titled "Ads History" that lists every ad you have ever clicked on since your account's inception.
The ZIP file also contains the entire list of third-party apps that you have installed on or linked with your Facebook account. It has IP addresses you've logged in from, email addresses, contact numbers of all friends you have added and pages you have liked; even all your phonebook contacts from Android smartphones you have used to log in to the Facebook account. Apart from that, it contains metadata on Facebook events, your friend list, messages, places you have checked into, videos you have uploaded/ been tagged in, and also every like and poke you've made.
To remove this access, you might have to completely delete (not deactivate) your Facebook account. If that is not an option, you can limit access by changing your preferences and revoking access to third-party apps. The latter can be done by going into Account Settings > Apps > Logged in with Facebook and removing the apps you wish to revoke access from.