Unlinked!

A long, long time ago on the Internet, friends kept sending me e-mails inviting me to sign up for something called LinkedIn…so I did. Since then, I've gotten thousands of messages — some from people I know, many from people I don't know — that read like this…

Hi Mark,
I'd like to join your LinkedIn network.

Sometimes, I say yes. Sometimes, I say no. I have no idea what any of this means. I apparently have a LinkedIn network but I have no idea what it does for me or anyone.

Every now and then, someone "endorses" me as a fine writer or a good human or a snazzy dresser or something. I have no idea what this does, either. I see no way in which LinkedIn has ever affected my life or connected me to anyone except that apparently they get to be on my "network" which appears to be meaningless.

What am I missing here? Can anyone point me to a primer for this service so I can get some idea of what it's supposed to accomplish? I mean, besides getting me more e-mails from strangers who want to join my LinkedIn network. Thank you.