I've had a LinkedIn account for over 11 years now. Pretty much the only thing that it has done for me is caused a few hundred salespeople to look up my contact information and try to sell me something.
Agree, I have 500+ recruiter/sales spam (http://i.imgur.com/W92SuAH.png) which I never check. I still have an account on LI because everyone else is there and I think I might need it but I have never used for anything useful yet.
