Underage users

Can someone explain to me why Youtube/Facebook/MySpace/Bebo/etc allow a child of the age of 11 years old to create an account on their sites without even attempting to verify their age?

I realise it states to put in a DOB, but most of these kids put in a fake one. Why not FORCE verification on the user by way of credit card, etc. If a kid wants an account their parents require a c/card to be verified.

>>2
We really need to stop kids using the net and then getting in trouble! Because if we don't It'll just cause more censorship to happen against all us becuase of all the whiny parents who don't teach their kids net safety. Moot should really think about some kind of age verification on 4Chan too before this place get closed down by pissed off parents!