So, here is one more niche social network targeted for high schoolers. Create a profile and get connected with classmates.
"Sconex is the unofficial website for your high school - a place where you can read about your classmates, share stuff with your friends, and communicate with people from your school and nearby ones."
What you can do?
Create your own mini blog and post messages.
Upload and share photos.
Share your thoughts and ideas.
Configure your public and private profile.
Discuss about your favorite subjects.
Teach each other.