18-24 year old face most ID theft risk

Bangalore: Mary Madden, senior research specialist at the Pew Research Center's Internet and & American Life Project, said 72 percent of millennials use social networking sites daily, compared with 40 percent of adults 30 or older.

She said young people share personal information about themselves, whether it is their birth date, phone number or a picture from a party, as a way to nourish relationships.

"You are trading information about yourself as a form of cultural currency," Madden said. "By posting a photo or an update about what you did at a bar last night, you are sharing with friends to initiate an exchange and continue a friendship."

Problems arise, she said, when the information is misused.

"It's an interesting balance they have to strike in deciding how much to share in order to initiate or maintain a relationship but not overshare with their network," she said.

Madden pointed to studies that show most people can be identified with three pieces of information: their sex, Zip code and date of birth. And seemingly anonymous profiles that catalogue preferences, such as movie lists on Netflix, can also be used to identify users.