LinkedIn is a social network for sharing work experiences.
It's great for research firms or job hunters.
It's so useful that, even if their annual revenue is about $3 million, the value in the stock market is near to a billion dollars (Yeah, it's unbelievable, it's a bubble)
What I hate about them is that they bug me if a friend of mine will join their website, sending me an invitation, and many reminders to join their website
Of course, as in all "evil" companies, there is no "remove me" or "opt-out" link in the email or website.
You have to contact them and ask to opt-out, and, after a few hours, their customer service will confirm the deletion 