I have had good results with looking up the male spouse of female relatives. As it turned out, they didn't know who the female spouse was because they were researching the male's family. I was able to fill them in with a missing name plus their descendants.
We hope that many of you will find this project of real interest and wish to participate. If you have any questions please contact our Group Administrator, Elizabeth O'Donoghue at firstname.lastname@example.org.