I used to be able to remember loads of phone numbers of family and friends etc.
When the Mobile phone came along i had only to press a certain key and "hey presto" the number appeared. Saved me a job.
Now my phone, if i try to add a new number asks me to delete an existing one because the memory is full. I will go through the phone book stored in the phone and come across some entries that i don't recognise, either because i haven't used that particular number for ages or i my have entered the name incorrectly.
What is my point?
Well imagine you are unconscious and a complete stranger, like a Police or Ambulance person is trying to contact your 'Loved One' or 'Next of Kin'... They find your mobile but what number should they dial?