I am sorry if a similar question has been answered before here.
I have been out of Facebook for at least 4 years now, but I had to recently create a throwaway account to access a closed groups so I could receive specific information about a test I was studying for. I joined in, also joined some random groups and the specific group I needed to be in. Accepted a few random friend requests from unknown people (asked myself several times why on earth people add total strangers to their account, not even knowing if it is a real person or a robot) so it wouldnt look as a throwaway (I feared I wouldnt be allowed in the group if it looked too obvious). Put a generic office photo in the header image and a picture of an animal as the avatar.
I have never accessed that Facebook account without using TOR.
I check the account once a day just to see if there is any new info I need in the group.
Well, today on the home page the first person in the “friends you may know” list the first person was a person I do know, who worked in the same place as I did a few years ago, and that I haven’t had contact in years. More like a friend of a friend.
I have taken every precaution I knew of to ensure the throwaway account I used there could not be linked to my real location or any other information about my real identity, but it seems not to have worked.
So I would like some help understanding how facebook did it and if there is any other precaution I can take to prevent it from happening again.
Thanks in advance.