For much of the past four decades, Mr. Graham leaned on his friend Warren Buffett for advice. But Mr. Zuckerberg's Web savvy makes him a valuable guide going forward in the digital world, even if Mr. Graham is old enough to be the 27-year-old's father.
"Warren is unique," Mr. Graham said, noting the Berkshire Hathaway chairman had made an "incalculable difference" over the years providing direction. "Mark is an adviser in different ways."
Mr. Zuckerberg has helped Mr. Graham think through a number of online initiatives in which the Post Co. has attempted to harness the power of Facebook and other social-media sites.