Jakob Nielsen conducted a reasonably large study of website usability with teenagers, covering a range of website types, in both the US and Australia.
Many people think teens are technowizards who surf the Web with abandon. It's also commonly assumed that the best way to appeal to teens is to load up on heavy, glitzy, blinking graphics.
Our study refuted these stereotypes. Teenagers are not in fact superior Web geniuses who can use anything a site throws at them...
Teens' poor performance is caused by three factors: insufficient reading skills, less sophisticated research strategies, and a dramatically lower patience level.
Usability of websites for teenagers - article by Jakob Nielsen
The Newspaper Association of America Foundation's commissioned research makes for some interesting reading. I feel content managers of information-driven websites such as universities can learn a fair bit from these findings. In particular, "If It Catches My Eye: An Exploration of Online News Experiences of Teenagers" and "Youth Media DNA" caught my eye.
Teen user research reports - The Newspaper Association of America Foundation