Freaky Facebook Continued

OK I just got home and got totally freaked out- Facebook how do you know so much about me!?!!?!?!? The person in the add a friend corner was a girl who I met in Europe 8 years ago....and she is from Canberra Australia!! AUSTRALIA! We have no friends in common and I knew her for 6 days- soooo scary! How the hell does facebook know that?!