Mark Zuckerberg has a reputation as a billionaire boy wonder and is often compared to a young Bill Gates. The chief executive of Facebook attended his own keynote speech in blue jeans and a hoodie at the f8 conference today in San Francisco. In his speech, he stayed on message.

But at a press conference afterward, he showed more of the real Zuckerberg. Most people haven’t met him in person or heard him talk unplugged. So these two videos are interesting because they offer insight into the way he interacts, answers questions, and behaves when unscripted.

The questions covered matters such as Facebook’s respect for user privacy and “what it wants to be when it grows up.” I noticed that he seems more comfortable and casual in discussion with the press than he used to be. And he has a command not only of the company’s big picture, but lots of the technical details behind Facebook’s platform as well. (Yes, that’s not surprising for a geek, but he’s a billionaire geek).

The crowd got a good laugh when Zuckerberg forgot not one but both questions that BBC reporter Maggie Shiels posed to him. He said, “I’m serial,” meaning that his brain processes questions one at a time, and shrugged his shoulders.

One other thing we learn: Facebook gives its internal projects code names based on economics, such as GDP. (Actually, he was making a joke about that and GDP stands for Granular Data Permissions). He may not be wearing a tie, but Zuckerberg is still thinking business.

Here are a couple of videos that are excerpts of the press conference. (For the complete press conference, see Robert Scoble’s video).