LinkedIn is designed to connect people together, so that in people search and other related areas and LinkedIn will show a connection distance between two users.

E.g., Bob connects with Alice, and Alice connects with Frank, assuming there is no other connections, then Bob and Frank's connection distance is 2.

Examples:
Bob: ["Alice", "John"]
Alice: ["Bob", "Frank", "Lucy"]
Frank: ["Alice"]
John: ["Bob", "Jenny"]
Jenny: ["John", "Lucy"]
Lucy: ["Jenny", "Alice"]
The connection distance between Bob and Frank is 2
the connection distance between Lucy and Bob is 2, although there is a connection chain for Bob → John → Jenny → Lucy, but Bob → Alice → Lucy is shorter