I have been working on my family tree since 2005. I had asked my father about his mother's family and he told me to ask a cousin of his whom seemed to know a lot more about this part of the family than he did. This cousin and I are particularly close and she lent me the copy of a tree that a cousin whom I never knew, made for one of my great aunts as a 90th birthday present; this great aunt married a first cousin so she never had any children. Her nieces and nephews were like children and their children were like grandchildren to her.
The cousin who made this tree, had been working on it since 1994 and on it was a cousin of my great grandfather but it only had her first name, her husband's and their son's first name but no last name. All I was told about them was that they were a part of the family who left Russia and went to England to escape the war.
I am a subscriber to certain list-servs and an email came through one from a woman in England looking for assistance in Philadelphia. Since I live close to Philadelphia, I wrote back and said I would help her if she in turn could try to help me...
Within an hour, I got an email with an archive from a Jewish Newspaper in London with a section that people put in personal ads looking for lost or missing family members; the fifth to last ad was from the brother of the cousin who
who had no last name, looking for her and her family.
The ad included the last name of the husband, which brought me back to Ancestry.com. I did a search on that last name, found a tree with a particular permuation of it, which included the cousin with the missing last name. I contacted the owner of the tree explaining the family relationship and within a day, this discovery also led me to finding the family in South Africa as well.
In less than 24 hours, not only did I have a last name for that cousin of my great grandfather, but I was able to add over 100 names to my tree!