They are more diligent than older adults, however, in trying to protect themselves. In a new study to be released this month, the Pew Internet Project has found that people in their 20s exert more control over their digital reputations than older adults, more vigorously deleting unwanted posts and limiting information about themselves. “Social networking requires vigilance, not only in what you post, but what your friends post about you,” said Mary Madden, a senior research specialist who oversaw the study by Pew, which examines online behavior. “Now you are responsible for everything.”