(SAN FRANCISCO) -- Facebook CEO Mark Zuckerberg announced a dramatic redesign of its users' personal pages, introducing a feature called Timeline to help people share their life stories with friends online, and updating another called Open Graph so users can see and hear the music or movies their friends like.
"Facebook's mission is to make the world more open and connected," Zuckerberg said to a packed house Thursady at F8, the company's annual conference in San Francisco for software developers and entrepreneurs. Timeline, he said, will be "all your stories, all your apps, a new way to express who you are."
Zuckerberg said Facebook's current layout -- the so-called Profile pages on which users post notes about their lives -- had become unwieldy. New posts crowded older ones off the bottom of the page, even if they were important in telling friends about a person's life.
Timeline, he said, will improve that. As time goes by, it will automatically help users by saving the important items and shrinking the lesser ones.
"It's really cool. It's really fun to fill out your timeline," he said.
Zuckerberg paced back and forth across the stage as he spoke to his audience of about 2,000 people, often giggling as he spoke or reacted to a video demonstrating a new feature.
He was introduced by Saturday Night Live actor Andy Samberg, who did a spot-on impersonation of him -- looking more like Zuckerberg than Zuckerberg himself in a hoodie and T-shirt.
"We're gonna change the universe!" shouted Samberg. Then, after a pregnant pause: "I say that every year."
The audience roared with laughter, and Zuckerberg laughed too.
But the Facebook update is serious business for the company, which has partnered with the movie provider Netflix, the music service Spotify and many others. Through Open Graph, said Zuckerberg, users will be able to hear what music their friends are listening to simply by moving their cursors over their friends' images.
How Facebook users will take to the changes is an open question. Many objected loudly when the social media website updated its look in smaller ways earlier this week.
Zuckerberg said Timeline will start Beta testing immediately. He said users' experience on the site has been "rethought from the ground up."
Copyright 2011 ABC News Radio