JUDY WOODRUFF:

And we take a broader look at digital political strategies now with William Powers. He is a research scientist at the Laboratory for Social Machines at the MIT Media lab. Brian Donahue, he's a veteran of the 2004 Bush-Cheney campaign, and a former official at the Republican National Committee. He's a founder and partner at CRAFT Media/Digital. And Hank Green, who was one of the YouTube stars to interview the president today, he has more than two million subscribers to his YouTube channel.

We welcome all of you to the program.

Hank Green, you just did a first-of-a-kind sit-down discussion with the president. How did it go?