Yuniti is one and it includes a good Parent's Guide.
http://www.yuniti.com/
Poptropica and Club Penguin are two.
bebo
Most kids, lie about their ages. Some don't. Myspace is a world wide networking center. And is for adults. Kids do things that they shouldn't be doing on websites like, "facebook, myspace, twitter...etc." And some adults just don't find it safe for their children.
Well u have Myspace,Twitter and Facebook.
Runescape
Twitter,MySpace,Well those are the most popular.
meez,hi5,and facebook
peoplewordsforkids.com
everloop
Some are FaceBook, MySpace and MSN profiles...
A variety of websites offer long surveys that can be used on MySpace. Some of these websites are Long Surveys, Bzoink, My Survey Vault, and MySpace Survey Fun.
Facebook, MySpace, YouTube, and Twitter.