Should I worry that my teen prefers reading Wikipedia, online forums, and fan sites over longer-form texts, such as books?
Short-form electronic reading is a recent trend in kids' and teens' reading habits, and the extent of it and the impact are just beginning to be explored. A small body of research has begun to examine the connections between reading short-form electronic text (social media posts, texts, emails, Wikipedia entries) and other factors such as phonemic awareness (letter and word sounds), long-form-reading comprehension, writing skills, and critical thinking. But much more research is needed to understand how short-form reading affects kids.
National long-term studies show that teens' reading proficiency has stagnated over the past 40 years. So school performance is a good place to look to determine whether your child's preference for short-form, online reading has had any negative effect.
It's certainly a positive sign that your teen is eager to satisfy his curiosity by reading, and he's fortunate to have such easily attainable material. Still, reading a variety of materials is best for comprehension, subject knowledge, and overall literacy. Bottom line? Let him stick with Wikipedia but encourage him to incorporate other sources -- online, printed, and multimedia -- as well. Check out Common Sense Media's teen book recommendations such as the Amazon Best-Sellers for Teens, Award-Winning Books for Teens, and Best Book Series for Teens.