I think LinkedIn can be a meaningful tool. It just cracks me how many invitations we all get with the default "since you are a person I trust" greeting. Particularly when they come from people we don't actually know.
A friend of mine who used to run a high profile investment fund told me he gets 20-30 LinkedIn requests a day. He's seen a noticeable surge in the last six months, which struck me that LinkedIn is probably a good barometer of the career anxiety we're all facing.
So many of these interactions start and end with the LinkedIn invitation. Social media of any stripe is a means to an end. It can be incredibly productive, but I think it takes focused attention to stand out from the herd. Otherwise, it can give a false sense of security.
And I think a small number of meaningful, serendipitous interactions will yield better results than a flood of general, superficial ones.
It reminds me of this post from Seth Godin defending why he doesn't use Twitter: "I don't want to use a tool unless I'm going to use it really well. Doing any of these things halfway is worse than not at all. People don't want a mediocre interaction."
Seth went on to create a private social network called Triiibes, which he occasionally opens up to new members. It works well because membership is capped and you're encouraged to be an active member, not a passive bystander.
(After I finished this cartoon, I suddenly remembered I drew a very similar one back in 2002 when I was about to graduate from business school in a down market. The more things change, the more they stay the same.)