"Daniel Morales, 58, was taking part in a New York project in which homeless people are given a prepaid mobile phone to keep a record of their lives.
"He had been updating his 3,000-odd followers with regular Twitter updates.
"Three weeks into the scheme, he decided to use it to track down his daughter."
Its hard to believe that just 20 years ago there was such a thing as losing touch with people. You might met someone while back packing and exchange nail mail or land line phone number ids. Younger readers may never have used either of these technologies. If someone moved both would be lost.
So for college student backpacking through Europe, it was an opportunity to make friends that could be thrown away easily.
Today a visit anywhere in the world is more likely to result in a swarm of new Facebook contacts. So now you have to let people know you are not interested in them anymore.