Consider this required reading for any teenager who feels invincible amid the online world, or any adult who expects to be in the job market.

What you post online matters, as 10 students who had gained admission to Harvard University recently learned.

Almost 40,000 students applied for admission as one of approximately 2,000 members of the Class of 2021.

The 10 students who learned a very hard lesson were admitted in early December. Members of the prestigious university’s incoming class are invited to join an official Facebook group, which is moderated by university officials.

Often, splinter groups of students with similar interest form smaller social media groups, as was the case this year. Specifically, these students sent one another images with captions that were racist and anti-Semitic and that made light of pedophilia, among other offensive themes, according to NPR.

Like many other universities, Harvard has a policy of revoking admissions offers if an applicant does not graduate high school, has plunging grades in their last semester, is found to have lied on their application or engages in other morally questionable behavior. This can include online speech. However, these policies are rarely invoked.

While this might at first seem like an infringement of First Amendment rights, students who are accepted at Harvard must sign an honor code to be good and virtuous when they apply.

The message for today’s youth is that your message matters. And if you put your message in the public domain, there is no controlling who consumes your message.

The momentary satisfaction of posting a crass remark isn’t worth the potential long-term effects. The lessons these students learned before they actually enrolled in college have bearing for us all.