The greatest value I see in LinkedIn is that it's one of the best places you can have PvP encounters with delusional C-suites making ridiculous claims in a world economy-defining hype bubble. Do I particularly think I am doing anything to change their minds? No, but I figure if enough people saw, at least some class consciousness could be built enough to resist some of their most inane excesses.
That's the first I've heard of LinkedIn-driven revolutionary endeavors towards social change. I think that's the point we've all reached given all else has failed.