Mark Zuckerberg, the philanthropist

A different picture of Facebook founder Mark Zuckerberg is emerging than the one Aaron Sorkin would have you see.

Instead of the fictional Zuckerberg who comes off awkward, insensitive and ruthless in “The Social Network,” the real Mark Zuckerberg is turning out to be – well, a mensch.

This morning, Bill Gates and Warren Buffett announced that Zuckerberg, 27, and Facebook co-founder Dustin Moskovitz (Jew? – joke.) would join The Giving Pledge, a campaign helmed by America’s wealthiest men to donate half their net worth to charity. The Facebook founders join another 57 billionaires who have committed to the pledge, including a coterie of Jewish givers like California residents Eli and Edythe Broad, New York City Mayor Michael Bloomberg, Orthodox Jewish investor Ronald Perelman and media mogul Barry Diller and his wife, the fashion designer Diane von Furstenberg.

The commitment itself stands on its own merits, but that Zuckerberg and Moskovitz are the youngest to take up the challenge brings a different sort of prestige. Barely pushing 30, the future of both of these men is uncertain. There is more risk in their commitment; their pledge requires more faith.

For one, neither one of them yet has a family, which inevitably complicates plans for distributing wealth. Although the absence of those considerations frees them to do their will. On the other hand, what if they suffer a bad investment? Or what if their priorities change?

The lesson Zuckerberg and Moskovitz come to teach us is that it doesn’t matter. There are no circumstances of life in which it isn’t appropriate to give as much as you can. And the beauty of The Giving Pledge is that is doesn’t specify where or to whom the billionaires must give, it simply insists that they do.

“People wait until late in their career to give back. But why wait when there is so much to be done?” Zuckerberg said in a statement. In addition to the billionaire pledge, Zuckerberg committed $100 million to Newark, New Jersey public schools last September.

“With a generation of younger folks who have thrived on the success of their companies, there is a big opportunity for many of us to give back earlier in our lifetime and see the impact of our philanthropic efforts.”

That hardly sounds like the same egotistical anti-hero we meet in “The Social Network,” whose myopic focus on realizing his vision renders him incapable or uninterested in most worldly concerns. Instead, Zuckerberg broods. He builds. He hurts people.

But what Mark Zuckerberg has created since those early Harvard days when immaturity and sexuality reigned, has enabled the most extraordinary transformation from self-centeredness to selflessness.

Zuckerberg always said he built Facebook to change the world. Now he can.