This is kinda stupid but I am needing some advice. Say that there is the kid who is not 13...and on forums....should I tell on him? I am not sure the "danger" he is in but it's against TOS. I am 24 and not wanting to ruin anyone's fun.

It depends, if the forum has a 'mature' feel then yes. If he is making problems yes. But if it's an 'all ages' forum then I don't see a problem with that.

Well, the forum banned another member for not being 13 so this is why I was asking.

Well then i take it it has 'mature' content then I guess you should then.

COPPA dictates that no personal information can be stored from an user under the age of 13 and an e-mail address is considered a piece of personal information hence why forums cannot allow anyone under the age of 13 from having an account on a forum. it is also in the IF's TOS and if not followed will mean the closure of the board if they see a violation of their TOS and it warrants board closure then they will do it hence why that forum probably restricted that underage user from having an account on there.

However if an underage user either fakes or fails to provide their age then the forum owner is not at fault for having them on there if they can't be proven to be underage either by them posting it somewhere or displaying it in their profile.

So what am I supposed to do? Give him up or forget about it?

If you can prove he is underage by finding something on the forum then yes.

However, if there is nothing on the forum that tells anyone that he is underage then no you don't have to.

COPPA guidelines also state that if a child under 13 tries to join a forum, the parents MUST send a letter in writing to the forum's administrator allowing the child to join. If the parents fail to send said letter, the child under 13 may not join.

I really don't know of any non-invasive way to prove that a child under 13 is accessing the forum you are on, so at the moment I don't know what to tell you.