I don't know too much about it.
Neopets are cyber creatures who steal children! Just kidding lol. Well, they do sort of steal children in that my own kids love going to Neopia. You can subscribe and pay a monthly fee for "upgraded features" but my kids have just used the free ones for the last couple years and it's always been enough.
It is a safe place. Under 13 must have written parent permission to get neomail and go to message boards and guilds. Even when you give them permission, they can only get messages from "neofriends." I do check occasionally to make sure she didn't add any strang neofriends but it's sort of hard to do. You have to send a shop written request to a prospective new friend and they must accept before you can communicate