I don't really use LinkedIn, so none of the listed problems apply to me, but I still have a complaint of my own. For me, its worst problem is that it's taken the #1 Google result for my name, just because I made a profile there way back in high school.

I admit that I have gone back every couple years to keep my out-of-date information on LinkedIn from becoming too misleading. However with zero connections, zero groups, zero messages, and nearly zero relevant content about me, there is no good reason for my LinkedIn profile to have such a high ranking.