单项选择题

Cameron Walker learned the hard way that sharing information online can have unintended consequences. In 2005, the sophomore at Fisher College in Boston organized a student petition dedicated to getting a campus police guard fired and posted it on the popular college social network Facebook. com. Walker wrote that the guard "loves to antagonize students.., and needs to be eliminated. " It was a poor choice of words. Another student informed school officials, who logged on and interpreted the comments as threatening. Though Walker claimed he was trying only to expose the guard’s demeanor, he was expelled. He’s now enrolled at another college and admits he made a serious mistake. "I was a naive 21-year-old," he says.
Creating a page on a social-networking site is now a cherished form of self-expression at universities around the world. Students use ad-supported services like Facebook, MySpace, TagWorld and Bebo to make friends, plan their Social lives and project their personalities. The most popular site among college students is Facebook, with more than 8 million members. A student’s personal Facebook page is usually a revealing, dynamic chronicle of campus life—one clearly not meant for the eyes of parents, teachers or anyone else older than 25.
But adults are taking notice. Sites like Facebook are accessible to nearly anyone willing to spend the time to gain access: teachers, school administrators, even potential employers and the police. Such online services can create the illusion of privacy where none actually exists. Facebook, in particular, was designed to emphasize privacy and intimacy. Only other users at your school (with the same college e-mail domain name), and those in networks you join, can see your home page. But determined off-campus visitors can persuade a student or alumnus to help them access the student’s page.
What happens when the identity you reveal to friends suddenly overwhelms the facade you present to grown-ups The results can be awkward—or worse. Photos from drunken parties, recollections of sexual escapades, or threats—all these indiscretions, posted online, have gotten students suspended or expelled, or harmed job prospects. In a couple of decades, a presidential candidate may be called on to answer for a college misadventure that he or she impulsively detailed in a blog entry.
Not all students want to temper their behavior. They point out that the Internet lets them express themselves and find like-minded souls. Still, adults aren’t likely to stop prying any time soon. That means students who use Facebook and MySpace have a new burden. The Web may seem ephemeral, but what you casually post one night might just last a digital eternity. While social networking represents a powerful tool for today’s students, they’re advised to be prudent. Even if they have no plans to run for president someday.
Cameron Walker was kicked out of school because he