Mark Zuckerberg is channeling Steve Jobs here at Facebook’s big launch day. A giggle just went through crowd at his presentation of the three key elements of his announcement, complete with choreographed hand gestures and reiteration: “deep integration, mass distribution, and new opportunity.”

Zuckerberg already handled a hiccup in the slides pretty well, admitting, “Facebook is the sixth most trafficked site in the U.S… and we can’t seem to get our act together.” And of course, the ambitions are intact: “We recently passed eBay in traffic, and we’re working on passing Ggogle too.

“Every once in a while a platform comes along that allows people to build a completely new application — sometimes even starts new industries,” is Zuckerberg’s message.

The justification for applications was explained by using a favorite trope of Om’s: the value of a network. Zuckerberg talks about the tremendous growth of photos and event applications built internally at Facebook, compared to applications built outside of the context of a network. Three times more people are invited to events through Facebook than Evite, he says, and Evite is only about events. With photo-sharing, he explained, “it’s not just the photos that spread, it’s the whole photos application.”

Third-party applications won’t be treated like second-class citizens on Facebook, he says; users can add them to their profiles and drag them and drop them to their content. Applications can use Flash, JavaScript, and Silverlight if a user approves them. Outside applications can issue unlimited notifications to users, and fit into the Facebook environment by accessing a “friend selector” that spits out each users’ connections.

Now Zuckerberg says you can serve ads on your app pages and keep all the revenue, sell them yourselves or use a network, and process transactions within the site, keeping all the revenue without diverting users off Facebook. This was the opposite to what was stated in the WSJ article earlier this week, and gets by far the biggest reaction from the crowd.

He’s demoing apps now, including nice video functionality where you can record from your internal camera, and embed it in a page. Now Dan’l Lewin of Microsoft is rubbing in the fact that he’s a lot older than Zuckerberg. Next is Amazon: Russ Grandinetti says FB members can review books. Max Levchin of Slide talking about Facebook as an operating system, a social computing system (familiar?!).

Aside: I should note that it’s not clear that this is actually launching today. Developer partners in the crowd told me before the keynote that even they weren’t sure when it would go live. So yeah, a lot of big talk, but keep that in mind.

Wrapping up now: Zuckerberg says more than 65 companies built apps for today. Thanking platform development team. Oh, finally! The platform will go live tonight.