Facebook Timeline, Open Graph and Ticker were some of the key words and features Mark Zuckerberg introduced to the thousands of users watching online and in person at Thursday's Facebook f8 2011 Developer Conference in San Francisco.

The other big feature was Andy Samberg, who opened the conference dressed in his Mark Zuckerberg best: hoodie, jeans and Adidas sandals.

Welcome to f8 . . . I want to start by focusing on some key issues. The first is the importance of authentic identity, Samberg said on stage. I am Mark Zuckerberg. And under this sweatshirt are rock solid, cut and greased abs.

Samberg, a Saturday Night Live regular and member of popular comedy rap group The Lonely Island, later received a loud chuckle from the live audience when he talked about Facebook's share feature.

The trend is toward more sharing. You wake up, share it with your friends. You're out of toothpaste, share it with your friends. You take a crazy big number two, don't share it with your friends. That's for Twitter, he said.

The real Mark Zuckerberg, in tennis shoes, joined Samberg at the end of the nearly 8-minute introduction. For the record, the real Facebook CEO showed up in tennis shoes, not sandals.

This is not the first time Samberg has impersonated the Facebook boss. In October 2010, the SNL star appeared on the show's Weekend Update segment as Zuckerberg, again, dressed in a hoodie, jeans and sandals.

My one regret with Facebook is poking. Poking is creepy and lame and getting an e-mail saying that your dad poked you is an enormous bummer . . . for that I apologize, Samberg said.

Here are some other highlights from Andy Samberg at Thursday's Facebook's f8 conference, in his Zuck best:

We're gonna change the universe! I say that every year, Samberg said after walking on stage to All I Do Is Win by DJ Khaled.

New features on Facebook, according to Samberg: A new section in your list of friends . . . it's called 'I'm Not Really Friends With These People.' It's the perfect place to put awkward classmates from middle school, older drunk women you meet at charity events, racist neighbors and aunts.

The Slow-Poke: It's the only poke that takes 24 hours to reach the person you sent it to, so you have a full day to sober up, realize you're an idiot and retract the poke, explained Samberg as Zuckerberg.

The 'Bergs: Look at us up here right? This truly is a gathering of the 'Bergs, said Samberg, who went on to impersonate Jesse Eisenberg and Mark Wahlberg.

Beast: Samberg gave Zuckerberg's dog two shout-outs, one to the pooch's popular Facebook page and the other as he walked off the stage.