Tweet Nicely, or Don't Tweet at All: How Twitter and Facebook Can Torpedo Your Application

Kaplan Test Prep surveyed 381 admissions officers, and found that 31% review applicants’ social media as they consider an application. Of those, 30% discovered something negative about the student. Some admission officers say they will reject students because of what the officers find within students’ social media.

See The New York Times, November 12, 2013: 

Photo: "And so it Begins. Shot of the Engineering Quad at the University of Colorado at Boulder. From one of the first days back :("  12.7.09  Courtesy Zach Discerner