Shared Matches was unveiled in August 2015 to show you other matches you share with a specific match. For example, say your dad’s brother’s son—your first cousin—is among your DNA matches. Click his name on your match list, then the Shared Matches tab. You can see everyone else who matches the two of you. Because you know your cousin is from your paternal side of the family, you can start looking there for a relationship with those Shared Matches.
Note that just because you and another person have a Shared Match doesn’t mean that all three of you have the same segment of DNA—that is to say, you all don’t necessarily have the same ancestor. Say you’re person A and you match person B. You and B have a Shared Match, person C. You match person B because your dad is first cousins with B’s mom, and you match person C because your mom is second cousins with C’s dad. But person B might match person C because B’s dad is cousin to C’s mom. In this case, you share a DNA segment with B and a