On Facebook's 10th Birthday, Mark Zuckerberg Reflects on the Long Journey of Creating a Social Media PowerhouseIn an exclusive interview with the 'Today' show, Zuckerberg says Facebook remains focused on its next big move.

"At launch, we were hoping for 400 or 500 people. Now we're at 100,000 people. So who knows where we're going next."

That's whatMark Zuckerbergtold CNBC in a 2004 interview, at age 19, shortly after launchingFacebook. It's funny how things change. Fast forward a decade and the social network is nowused by 57 percent of all adultsand 73 percent of all those ages 12 to 17. It seems likeFacebook is more addictive and widely used than ever.

In an exclusive interview this morning with theTodayshow, Zuckerberg reflected on the long journey of launching a product that changed the way people all over the world interact. (For so much change, it's also funny how some things never change: Zuckerberg wore his signature dark hoodie for the interview.)

"I remember really vividly, you know, having pizza with my friends a day or two after -- I opened up the first version of Facebook at the time I thought, 'You know, someone needs to build a service like this for the world,'" Zuckerberg told theTodayshow's Savannah Guthrie. "But I just never thought that we'd be the ones to help do it. And I think a lot of what it comes down to is we just cared more."

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Make no mistake, though, it hasn't been all smooth sailing for Zuckerberg and his team at Facebook. There have been repeated privacy issues, a rough IPO opening day, issues dealing with the NSA and that nasty rumor about teenagers becoming bored with Facebook and leaving in droves.

"We've just gone through a number of periods where people just didn't believe that we could succeed at what we were trying to do," Zuckerberg said onToday. "I've spent a lot of late nights pacing around my living room with teammates, right, just trying to plot out what our next move can be in order to keep pushing forward on this mission. There's always a next move.

Here is Zuckerberg's interview withToday:

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