You may know the person well, but you do not know his email. Previously, you could not make contact with him. Now it is possible in the social network LinkedIn , where the other day greatly changed the procedure for dating between the participants.
Previously, in order to invite a person, you must have known his email address. This procedure led to the opposite results: people began to specially recognize the email addresses of strangers and send them invitations, in fact, turning into spammers. To fight spam, LinkedIn now has a new dating procedure. Now you can make contact with a familiar person directly from his profile. ')
To prevent abuse of the service, the addressee may indicate that he does not know you. And then the preferential mode of dating for you will be canceled - you will still enter the email. If there are five such “calls”, then your account can be closed altogether.