Here are some sites for teachers to set up classroom collaborations for practice with social networking. Most require registration. Some are adfree if you purchase a class subscription. Some require network setup.

Kidblog - quick easy set up.

Class Blogmeister Registration and set up needed.

Epals School blogs Set up needed

Gaggle.net Set up needed.

Moodle.com Set up needed.

21Classes Set up needed.

Edmodo Set up needed.

Today's Meet No registration needed to start a room for a backchannel. Students can use first names. Room can be temporary or remain up for up to a year.

Wallwisher Changing name to Padlet. Teacher must register, but can set up for students to add with just first name. Can set up that teacher moderates when comments are made public.

My Haikuclass

Schoolology