Internet website for children

Last time, I was talking about Naver as No.1 search portal in Korea, and NHN corporation, which owns Naver, has developed another search portal for children called Junior Naver(and there is well-explanation of the website in NHN). As Internet is widely distributed, we cannot neglect children are users of the Internet. Therefore, targeting the children has great potential for the Internet business. The NHN now corporates with many education and children game companies such as EBS (education channel in Korea) and NEXON, since this website provides lots of contents for children's education and entertainment.
There are more web portal for children in Korea such as Daum Kidjjang, and Yahoo kids Korea, and there is English version of Yahoo kids( I think it is not like "search portal" for kids in Korea, but just entertainment website for kids.) Check them out and see what's different.