Linked contacts

Hi

Linked contacts appear to be receiving copies of transactional emails.

How do contacts become linked?
Why would they receive copies or versions of an email?

I have noticed an instance where a user received a copy of an email meant for another, completely unrelated, user.

Donal

This would have to be a third party action. There is no native way in IS to communicate with a contact based on their being a linked contact.