Yesterday Ancestry.com announced the release of a new database, Social Security Applications and Claims Index,1936-2007. This database "picks up where the SSDI leaves off" and includes potentially valuable details such as birthdate, birthplace and parents' names. The entries come from information filed with the Social Security Administration through the application or claims process. Not everyone in the SSDI database is included. I did not find my parents nor my husband's parents nor any of their siblings in the database (the generation born between 1900 and 1920)  although I do see many other names from that era. It'd be helpful if we knew more about how these particular 49 million records were extracted. I saw the names of a few individuals born between 1875 and 1900 which had promise for my research. Anticipate misspellings and omissions, but there could be a good lead here. If you have an Ancestry subscription, query some of your 'mystery people' and see what you find. I'll report back later if I discover anything interesting.