Please tell me about Education city?

[user789653241]

Hello.
It seems like there's always tell a friend code thread is going on MN.
Seems very popular among Mnetters.
Is it good site? How good? What do they teach children?
We subscribe to another site and happy about it, but it doesn't have science content. I'm curious since it's so popular, it must be good.
Any opinion appreciated. TIA.