When I still had a social life, Facebook was returning the account simply by searching the phone number or email. So useful. I also loved the first release of

When I still had a social life, Facebook was returning the account simply by searching the phone number or email. So useful. I also loved the first release of graph search (not the dumbed down version they released shortly after) which was letting you specify very specific queries. I managed to find a girl I met on a train (whose number I stupidly didn't ask) just with her first name, university and knowing something she liked. Later on, trying to replace graph search, I had to write some hacky scripts to scrape data across a network of friends (likes, groups, friends, who interacted with you on your public profile + recursively scrape data from friends of friends) to find people.