At a conference six months ago, Facebook's 26-year-old chief executive was literally dripping in sweat as he fielded tough questions about his company's privacy practices and a forthcoming movie portraying him as manipulative and arrogant.

On Wednesday, a poised, perspiration-free portrait of Mark Zuckerberg graced the cover of Time magazine, which crowned him its Person of the Year, capping what may be one of corporate America's most remarkable transformations.

The make-over of Zuckerberg's public image has been hard to miss, with a high-profile donation to New Jersey public schools in September and appearances on television programs like The Oprah Winfrey Show and 60 Minutes. It has occurred as Facebook, the world's No. 1 Internet social network, sees its audience of friends and its influence swell.

Facebook may not need a smiling Zuckerberg to thrive, but it certainly doesn't hurt.

He is the face of the company, said Paul Argenti, a professor of corporate communication at Dartmouth's Tuck School of Business, who said The Social Network, the fictionalized film about Facebook's controversial creation in a Harvard dorm room in 2004, put (Zuckerberg's) reputation up for grabs.

He's been on a tear to repair that, Argenti said.

The film, which recounted claims that Zuckerberg stole the idea for Facebook from a separate project spearheaded by classmates (which led to a lawsuit that has been settled), came out at the same time as reports surfaced in online blogs suggesting Zuckerberg had shown a cavalier attitude toward Facebook users' privacy in the company's early days.

WHO'S BEHIND THE TRANSFORMATION?

The change is more than image-deep. The redheaded CEO, whose net worth was recently estimated at $6.9 billion by Forbes magazine, was prone to awkwardness in interviews in the past, with a demeanor that made him seem aloof.

But he has appeared decidedly more comfortable in his interactions with reporters in recent months.

During a recent discussion with reporters, he played with a boomerang and cracked jokes, nothing like the stiff and guarded delivery of previous encounters.

Whether Zuckerberg has simply found his comfort zone as a result of a string of back-to-back media briefings and product announcements, or extensive coaching, or a combination of the two, is not clear.

Facebook has its share of executives well-versed in public image, including Chief Operating Officer Sheryl Sandberg, chief of staff for the U.S. Treasury Department under President Bill Clinton.

Facebook spokesman Jonny Thaw declined to comment on the matter, but analysts saw Zuckerberg simply being more open.

One of the things he's done is he's made a conscious move to not let somebody else define who he is, but to go out and sort of let people know who he is, said Jim Bates, of the crisis communications firm Sitrick and Company, which has helped rehabilitate the images of such clients as R&B singer Chris Brown and celebrity socialite Paris Hilton.

Some industry insiders see the efforts to improve Zuckerberg's image as reminiscent of another out-sized technology figure. Bill Gates, the co-founder of Microsoft Corp, was often criticized for cut-throat business practices and a brusque personality during the 1990s.

That edge has softened in recent years, particularly as he has focused on philanthropic work, which earned him a share of Time magazine's people of the year cover in 2005, alongside his wife, Melinda Gates, and rock star-philanthropist Bono.

Of course, Gates, unlike Zuckerberg, is no longer running his company. Stan Kowalczyk, a professor at San Francisco State University who focuses on corporate reputation, said that gave Zuckerberg room to see another flip in his image if he was not careful.

He's going to have to walk on eggshells to make sure that he doesn't do something that is going to jeopardize that reputation, Kowalczyk said.

(Editing by Mary Milliken and Peter Cooney)

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