LinkedIn for Litigation?
Guy Kawasaki explains how to use LinkedIn's Reference Check Tool to avoid bad bosses. In essence, you can input a company name and a range of years to find people who worked at the company during a given time period.
This would be a great tool for locating potential witnesses in a litigation action. Input the plaintiff/defendant company name and the years before, during and after the actionable conduct. LinkedIn will serve up a list of people who may know a bit about company/facts/etc. Even better, they may no longer be employed and more likely to help you.