Barack Obama praises Facebook, but warns schoolchildren

Barack Obama today spoke directly to schoolchildren across the USA, motivating them to rise above their mistakes and challenges in order to succeed in school. “Students who sat where you sit 20 years ago“, the president said, “founded Google, Twitter and Facebook and changed the way we communicate with each other.“
My favorite moment of the entire speech was when this happened during a short Q&A:
STUDENT: Hi, Mr. President, my name is Jessie. When I grow up, I would like to have your job.
THE PRESIDENT: Okay.
STUDENT: Is there any advice you can give me, or career paths that I — things I need to know?
THE PRESIDENT: Well, let me give you some very practical tips. (Laughter.) First of all, I want everybody here to be careful about what you post on Facebook — (laughter) — because in the YouTube age, whatever you do, it will be pulled up again later somewhere in your life. And when you’re young, you make mistakes and you do some stupid stuff. And I’ve been hearing a lot about young people who — you know, they’re posting stuff on Facebook, and then suddenly they go apply for a job and somebody has done a search and — so that’s some practical political advice for you right there. (Laughter.) That’s number one.