I think it started off small but he knows a lot of people and the school is large.
I first saw the Stanford video on a private parent group page. All the acceptances are listed on the page and we all congratulate the students. He was filmed at a private home of a friend with his mother and close friends. I cry with joy every time I see the video and others have been touched like this. Therefore, the video spread. The rest has been an update to the story for people who cared in the first place. But I love graduation season any way.