I was thinking of closing my Linkedin, but it came down to this: Suppose I wanted to join a company / get to know someone and didn't realize that someone I alre

I was thinking of closing my Linkedin, but it came down to this: Suppose I wanted to join a company / get to know someone and didn't realize that someone I already knew, knew them? How could I figure out who knew who to give me warm intro w/o Linkedin? For that reason I'm probably going to keep my Linkedin until I find it unnecessary.