via Distriction, in a blog post called "Sign of the Times":

Stephon stood just a few feet away from Barack Obama. The president, busy shaking hands, looked right at him. “It was like he was waiting for me to say something,” he said later.

So the 26-year-old Prince George’s Community College student took his cue and spoke to President Obama in his first language: American Sign Language. “I am proud of you,” Stephon signed. The president, almost involuntary, instinctively, immediately signed back.

“Thank you,” Obama replied.

This is one of those moments that humanize the office of the presidency.

And recounted in Stephon's own words:

The moment I will never forget was when he looked at me. He gave me a chance to talk to him. It was like he was waiting for me to say something. I took the moment and signed “I am proud of you,” and his response was “Thank u” in sign language back! Oh my gosh! I was like wow! He understood me after I said I was proud of him. It was so amazing…I was just speechless. Right after he thanked me, he smiled at another deaf lady who signed “I love you.” When I shook his hand it did not feel like he was superior to me. He was just a humble man. I am just impressed by him and know that he will have my vote and he will win second term without a doubt. Yeah, I feel safe to have him for another term.

Team Obama have added the video to their own YouTube channel, here.