
Quoting
cbg
There are information-gathering websites out there that know a scary amount about you. They match up addresses, phone numbers, tax records, and various other things and can come up with a frightening amount of information.
If I run my own name on Spokeo or Zabasearch, I am reminded of emails I gave up so long ago I'd forgotten I even had them; they know my maiden name, my husband's name, and matches me up with my best friend, her deceased husband and her stepson. My best friend and I did share a house at one time, before either of us were married, but I never shared living space with her after she was married. Yet these search engines know that I have a connection with her husband, even if they get wrong what the connection is. One of those searches had me connected to someone whom I do know, have met in real life, but whose only real connection with me is that I've known her husband for twenty years in an loose employment context and she and I are Facebook friends. One of them has matched me up with my husband's ex. My picture is attached to someone who shares my first and last name but who has a different middle initial and who lives in the same state as me but in a town where I've never lived.
There are any number of connections that could easily match you up with someone to whom you're actually related.