It's a good website for tweens and teens. There's no bad language or anything, even in the comments because they're moderated. You need to go by sections though. Some sections aren't that great for 10 year olds, but ok for 13 or 14 year olds.
Guys: 13-14+, younger kids won't really need to go there, you know?
Advice: 12-13+, if anyone younger needs advice they can just comment on a random article with "MOD MOD MOD" at the top and a moderator can answer your questions or give you advice.
Fun Stuff: 10+, lots of cool ideas!
Style: 10+, but younger kids probably wouldn't care.
Health & Fitness: 11-12+
Quizzes:10+, I go there when I get bored
Mag: any age, it's just basically if you want to subscribe or know what's in the magazine.
Video: I don't know, I've never really visited that part of the website.