On the surface, it appears that little has changed for Amish youth in the past decade: children learn to work hard early in life, they complete school by age fourteen or fifteen, and a year or two later they begin Rumspringa--that brief period during which they are free to date and explore the outside world before choosing whether to embrace a lifetime of Amish faith and culture.

But the Internet and social media may be having a profound influence on significant numbers of the Youngie, according to Richard A. Stevick, who says that Amish teenagers are now exposed to a world that did...