At Apple, Tim Cook leads a quiet cultural revolution

SAN FRANCISCO: Shortly after signing on as chief operating officer at Facebook, Sheryl Sandberg was looking to connect with people in a similar role - No. 2 to a brilliant and passionate young founder. She called Tim Cook.

"He basically explained nicely that my job was to do the things that Mark (Zuckerberg) did not want to focus on as much," Sandberg said of the 2007 meeting that lasted several hours with the chief operating officer of Apple Inc.