Years ago I had a linkedin account. It was not so useful to me, because I could remember who I'd worked with, and I would ask for personal recommendations/feedback from friends who were local about companies near me.
I deleted the account because I was annoyed by too many emails "Bob Smith wants to be in your network". That on top of fake-recommendations was just too much.
Recently I was searching for some details on PXE booting, and I came across an article I'd written shamelessly copied and pasted with no attribution in their forums.
Reporting this to linkedin.com resulted in no action.
Submitting a formal DCMA-takedown notice to linkedin resulted in no action.
Poking them on twitter, twice, resulted in no action.
So, really, what are linkedin good for? Fake recommendations from people you've never met? Weekly spam about people who want to connect to you?
Update: Rejoined the site to see if I could flag/report it. No chance. Fuckers.