Facebook does the same thing and it's just as creepy. I closed my "real" account around 2011. A few months back I created a new blank account because I needed access to a couple organization's pages. The only information on that account is my name (a fairly common one) and an email address which is different from the one on my original account. It's possible they have some geographic info linking the two accounts as…
It pointed to me that I probably knew a profile.
This profile was a "fake profile" of a person I knew, from the description it was clear it was this person, can't tell which email was being used, and if I remember correctly it had no friends as well (or maybe only one unrelated friend)