I thought this might be interesting, John Cassisy at the New Yorker claims: "One more cautionary note: Don’t take too seriously the headlines you will see about the market valuing LinkedIn at $8-9 billion. Using the oldest I.P.O. trick in the book, the underwriters only issued 7.84 million shares, thereby creating an artificial shortage. Even at $90 each, the value of LinkedIn’s publicly issued stock is just $706 million. The $8-9 billion figure comes from taking the market price and applying it to the rest of the company’s common shares, more than eighty million of them which haven’t been issued yet. It may well be several years before all of these shares are trading on the open market. At that point, we will have a better idea of what LinkedIn is really worth."

http://www.newyorker.com/online/blogs/johncassidy/2011/05/li...