Twitter,MySpace,Well those are the most popular.
peoplewordsforkids.com
Runescape
everloop
terra monsters
kidswirl
do it on facebook
Poptropica and Club Penguin are two.
FanlalaEdmodoFantageClub Penguin
facebook, reddit, twitter, instagram, youtube
Here are a few: menewsha.com roliana.com
meez,hi5,and facebook