Why hadn't she been in touch before? I find it slightly far-fetched that she had actually tried to get in touch before, and the only way she managed was through facebook.
Maybe just the fact that it makes it so easy for people to look up other people. All you need is there name, and know what they look like. Pretty hard to do that anywhere else.
Unfortunately, lost phone numbers, non-permanent home address and the lack of a white pages made it impossible.