James Traub has a cover story in today's New York Times Magazine, "The Celebrity Solution," that's all about celebrity activism in global philanthropy and peacebuilding:

Stars — movie stars, rock stars, sports stars — exercise a ludicrous influence over the public consciousness. Many are happy to exploit that power; others are wrecked by it. In recent years, stars have learned that their intense presentness in people’s daily lives and their access to the uppermost realms of politics, business and the media offer them a peculiar kind of moral position, should they care to use it. And many of those with the most leverage — Bono and Angelina Jolie and Brad Pitt and George Clooney and, yes, Natalie Portman — have increasingly chosen to mount that pedestal. Hollywood celebrities have become central players on deeply political issues like development aid, refugees and government-sponsored violence in Darfur.

Increasingly, celebrities are taking an active interest in world politics. When media maven Tina Brown attends a Council on Foreign Relations session, you know something fundamental has changed in the relationship between the world of celebrity and world politics. What’s even stranger is that these efforts to glamorize foreign policy are actually affecting what governments do and say. The power of soft news has given star entertainers additional leverage to advance their causes. Their ability to raise issues to the top of the global agenda is growing. This does not mean that celebrities can solve the problems that bedevil the world. And not all celebrity activists are equal in their effectiveness. Nevertheless, politically-engaged stars cannot be dismissed as merely an amusing curiosity in foreign policy.

The truth is, reading his essay, I can't get too worked up about it. My essay was intended to be more of a meditation on why celebrities have become more influential. As a reporter-researcher, Traub does something in his essay that I didn't do in mine. He actually got the participants to confirm the causal mechanisms I only posited.

For example, here's what I wrote about the celebrity exploitation of "soft news" outlets:

In the current media environment, a symbiotic relationship between celebrities and cause célèbres has developed. Celebrities have a comparative advantage over policy wonks because they have access to a wider array of media outlets, which translates into a wider audience of citizens. Superstars can go on The Today Show or The Late Show to plug their latest movie and their latest global cause. Because of their celebrity cachet, even hard-news programs will cover them—stories about celebrities can goose Nielsen ratings. With a few exceptions, like Barack Obama or John McCain, most politicians cannot make the reverse leap to soft-news outlets. Non-celebrity policy activists are virtually guaranteed to be shut out of these programs....

The power of soft news is not limited to television. Vanity Fair let Bono guest-edit a special issue about Africa, knowing that cover photos of Madonna and George Clooney would attract readers and buzz. Without intending to, those perusing the pages might form opinions about sending aid to sub-Saharan Africa in the process.

In 2004, Natalie Portman, then a 22-year-old fresh from college, went to Capitol Hill to talk to Congress on behalf of the Foundation for International Community Assistance, or Finca, a microfinance organization for which she served as “ambassador.” She found herself wondering what she was doing there, but her colleagues assured her: “We got the meetings because of you.” For lawmakers, Natalie Portman was not simply a young woman — she was the beautiful Padmé from “Star Wars.” “And I was like, ‘That seems totally nuts to me,’ ” Portman told me recently. It’s the way it works, I guess. I’m not particularly proud that in our country I can get a meeting with a representative more easily than the head of a nonprofit can.”....

Portman didn’t have to do very much when she came back and became Finca’s international ambassador of hope in 2004; she simply made a point of talking about microfinance when she did any publicity. She appeared on the cover of Vogue and in the long story inside talked about her work with Finca. “The influence of that interview was huge,” says Christina Barrineau, then the director of the U.N. Year of Microcredit. “Anyone who Googled it immediately came to our Web site, and I was flooded with e-mails from young influentials who wanted to learn more about how they could help.”