On a hot summer day last year, Alexis and her Youth Unlimited leader headed to a local swimming spot. When they arrived, Alexis spotted some friends. Her leader suggested that they go over and talk with them, figuring she would be eager to chat with her friends. Instead, Alexis quickly replied, “Oh no, I couldn’t, I’ll talk with them over Snapchat when I get home.” At a season in life when friends and social acceptance are paramount, cell phones and social media offer teenagers a virtual world of instant and endless connectivity. Today’s...