LinkedIn has said time and time again that its desire is for its members to only connect with other members with whom they have had previous interaction, either through a shared work experience, school, or as a vendor. Members who don't yet know each other are encouraged to connect only after having been introduced or referred by a shared connection. That's why every profile that you see on LinkedIn is displayed as being either a 1st degree connection, 2nd degree connection or 3rd degree connection. 1st degree connections are people you are directly connected to, while 2nd degree connections are people with whom you share a connection, but you are not yet connected to directly. 3rd degree connections are members with whom you have no shared connections at all.