It's very important to set your place in a concrete environment. I think Chekhov said that the important thing when you have a play or any kind of novel is to set the roots in a concrete place.
LinkedIn allows you to search histories and CVs in your network - it's great for finding people who work in a particular company, or who have worked with someone you know. It's also an interesting way to find references for people or companies you're getting to know.