Zuckerberg in the hot seat at D8

RANCHO PALOS VERDES, Calif.--Facebook CEO Mark Zuckerberg defended his company's approach to privacy, saying it makes sense for users to have a mix of information: some that's shared narrowly and some that should be made broadly available.

"There have been misperceptions that we are trying to make all the information public," Zuckerberg said, speaking at the D: All Things Digital conference here. That said, for social networks to link people to one another, some information must necessarily be public, he said. "There's some serendipity that can only happen if you are sharing," Zuckerberg said.

In recent weeks, Facebook has (yet again) found itself under fire over privacy measures. The company attempted to assuage things last week, but concerns remain, including privacy issues around the company's "like" button. Facebook is also the subject of a new book by former Fortune staffer David Kirkpatrick.

Walt Mossberg pressed Zuckerberg on just how simple Facebook has actually made its privacy settings for its users.

"You've done some abrupt things," Mossberg said, referring to times that the company made information that had been private public, even if there was a way for customers to go back and make that information private again. "Why do I have to do the work?"

Zuckerberg said Facebook offers its users the option to change things from the defaults and noted that more than 50 percent of Facebook users have changed at least one setting.

"To me, that's a signal that we are, on the whole, getting it right," he said.

Zuckerberg rejected the idea that everything should be opt-in, pointing to things like the news feed that some people didn't like initially but that eventually became core features of Facebook.

"I think it's a balance on all of these things," he said. "I don't know if we always get it right."

Looking forward, Zuckerberg said he's seeing a trend of more personalized content across the Web, predicting that five years from now, people will be surprised at how little content was geared for the individual today.

"The world is moving in this direction," he said, "where things are going to be designed around people."

Asked whether Facebook will have an iPad-specific application, Zuckerberg said, "I assume [that] eventually we will...We're still a pretty small company."

He noted that the team that works on Facebook's news feed, which he said is the home page for 250 million people, is run by 11 people. The site's huge search volume is run by 12 people, and even the platform group, which he hopes will one day be the foundation of the whole industry, includes just 25 to 30 people.

"We have a lot more to do," he said. "I think that's one of the most exciting things about the next few years."

Zuckerberg was asked if he expected to be CEO when Facebook potentially has a stock offering. He said he plans on remaining CEO, but added, "I don't think about going public...much."

Zuckerberg said the best thing he and Facebook can do is stay heads-down on their plans, noting how fast the world is still changing. He said a lot of people expect the company to do less crazy things and to slow down. "I guess I hope we never do that," he said.

As for who he leans on, Zuckerberg said he has "a core group of people that I really trust, people that I've worked with for a long time--four or five years."

That last line drew laughter from the crowd, nearly all of whom are considerably older than Zuckerberg.

One questioner asked Zuckerberg how decisions are made at Facebook, noting that Google uses A/B testing, that Microsoft uses a lot of prototypes and beta testing, and that at Apple, well, Steve Jobs decides things.

"We're a company where there is a lot of open dialogue," he said. "We have crazy dialogue and arguments."

Zuckerberg said he still has an open question-and-answer session every Friday, during which staffers ask him hard questions.

"It actually should have been good practice for this [interview]," he said, though fellow Facebookers don't seem to mind him wearing hoodie sweatshirts like the one Swisher had him take off.

Among the final questions for Zuckerberg was where he stood on HTML 5 versus Adobe Systems' Flash, and on the Web versus software debate.

"We're agnostic, I think, on [HTML 5 and Flash]," he said. "I tend to believe more in the Web than apps." At the same time, however, he said processor and battery limitations make apps a necessity on mobile devices.

When he last appeared at D, two years ago, Zuckerberg said Facebook had fewer than 100 million users and had yet to launch its Connect service. On Wednesday he said the next two years would be as transformative, if not more.

Kara Swisher asked Zuckerberg about things he has said in the past, and the CEO said he has done things he's not proud of but said he wasn't able to say if instant messages recently attributed to him are indeed his writings.

"I cannot go back and change the past; I can only do what we think is right, going forward," he said.

Swisher said she knew Zuckerberg wasn't happy about an upcoming movie about him.

"I just wished that nobody made a movie of me while I was still alive," he said.