President Barack Obama warned America’s adolescents that your Facebook postings could come back to haunt you in a speech to students on Tuesday. Obama spoke to the nation’s young people on the first day of the school year for many in America, encouraging them to study hard and take responsibility for their own education.

“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 …” the President stated in an address live from Wakefield High School in the Washington suburb of Arlington, Virginia.

“First of all, I want everybody here to be careful about what you post on Facebook, 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 know, you make mistakes and you do some stupid stuff,” Obama said to a student who asked him what he could do to become president, too.

The president’s advice to high school students follows reports that many prospective employers may be mining social networking websites for background information on job applicants.