Nearly a quarter of college admissions officials check out an applicants’ Facebook page, according to a new survey from Kaplan Test Prep.

The popularity of smart phones and social networking sites is keeping a growing number of students connected—to danger, deception, and a loss of academic or career opportunities if they aren’t careful.

Many students haven’t set secure privacy settings on their profiles, and they might not realize how easy it is for a Facebook friend to spread embarrassing content from a private profile. Add in impulsivity, multitasking, and the ability to instantly post or text from a mobile device, and the results can be disastrous, said Sameer Hinduja, the co-director of Florida Atlantic University’s Cyberbullying Research Center.

“I’ve seen personal and professional damage occur to individuals who posted or sent something online that will plague them for the rest of their lives,” said Hinduja, an associate professor of criminology.

For example, an 18-year-old in Orlando, Fla., texted a nude photo of his 17-year-old girlfriend—and ended up on Florida’s sex offender list. A job applicant at a Miami Shores university ranted online about having to take a typing test, and lost the chance for the position. And a 13-year-old Hillsborough, Fla., teen killed herself after sexting photos were spread around her school.

As a result, colleges and school districts say they’re making internet safety a priority in their training efforts. They’re holding workshops, adding internet safety to freshmen orientation exercises, and counseling students as they apply for colleges or jobs.

In a recent session at Florida Atlantic University, Hinduja warned students to lock down their privacy settings and resist the urge to put profanity-laden rants and drunken keg stand pictures on their profiles.

The practice of sexting—using a mobile device to send out explicit photos—has become mainstream, with more than half of college students acknowledging they’ve sent or received such an image, according to a recent University of Rhode Island study.

Hinduja conducted a study on sexting at middle and high schools and found that 13 percent of children aged 11 to 18 had received a naked or semi-naked photo of someone from their school. Nearly 8 percent admitting sending a photo.

Hope Witsell, 13, suffered from vicious bullying after a suggestive photo she texted to a boy got out at her middle school, according to the St. Petersburg Times. She hanged herself in 2009.

In a high school outside of Milwaukee, at least 31 male students reported they were seduced into sending naked photos of themselves after receiving a Facebook request from a pretty young girl. But it wasn’t actually a girl. On the other end was an 18-year-old named Anthony R. Stancl, who threatened to expose the photos if they didn’t have sex with him. He was sentenced last year to 15 years in prison.

Sexting has also has led to child pornography convictions in Florida. The most famous happened four years ago when Phillip Alpert of Orlando, who had just turned 18, forwarded naked pictures of his 17-year-girlfriend to her family and friends after an argument. He is now a registered sex offender.

“He was unable to live with father, because his house was too close to a school,” said his lawyer, David Lawrence. “He got kicked out school and couldn’t get a job.”

Minors also have been prosecuted as sex offenders for sexting, although Florida passed a law this year that decriminalized sexting charges among minors for first-time offenses.

The stakes also are getting higher as more employers and colleges start to check out applicants through their social media pages and Google searches.