I find zero value in LinkedIn...
The concept isn't even original. It's been called a glorified Facebook for business professionals and LinkedIn doesn't deny it.
As I poke around my own profile I'm inundated with prompts to "upgrade" my membership to enjoy all those "premium" features like being able to actually get useful search results (instead of "professional at xyz") or send a colleague an "in-mail" message on the site.
Screw it, I'll just text them...
But you have to ask yourself, Why?
Why would I pay a subscription fee to get even more email from people I don't know? What most people consider spam, Linkedin considers a "feature."
I know, I know, these are supposed "business contacts" and "networking opportunities" not Viagra ads but that's rarely the case. For example, I've gotten more requests to "join someone's network" from cold calling "staffing specialists" (resume stackers) than anyone I've ever had an actual professional relationship with.
In other words, you'd get less spam from a Monster.com account than from an active LinkedIn profile. In fact, Monster.com is more useful which is something I never thought I would say. Yeah, they want a paid subscription too but at least the search function works!
LinkedIn has been having an identity crisis for at least the past 5 years with most looking at it as a job search site while others look at it as an expanded CV while still others bought into that whole Facebook thing.
I sincerely hope nobody is pinning all their hopes on the job listings. Most of them are out of date and/or list jobs that have little to nothing to do with your own skills.
If you do find something, expect to run into the service's many roadblocks including blocking the ability to share the position with anyone who doesn't happen to use the service. Worse, many ISP's consider email messages from LinkedIn as ACTUAL Spam so your friend probably wouldn't get them anyway...
If you think it works for you chances are you already had a deep contact list without LinkedIn's help.
Meaning that those at the top of the heap likely get deluged with "connection" requests from complete strangers unless they choose to block such communication.
Which kind of defeats the purpose...
I admit, I do check in now and again just to see who got fired. If you have enough information you can piece together just how flaky any given corporation's management is by watching how often different names show up under the same job title.
So I guess it's good for something but not for what it professes to be.
If you think LinkedIn is doing great things for your career you're just not giving yourself enough credit.