It's a good article and worth a read.
Link to Fortune article about Bill Gurley:
http://fortune.com/2015/03/15/bill-gurley-predicts-dead-unicorns-in-startup-land-this-year/
Link to Fortune article "The Age of Unicorns":
http://fortune.com/2015/01/22/the-age-of-unicorns/
Link to Fortune's "The Unicorn List":
http://fortune.com/unicorns/