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.

>>3
If it hasn't been shutdown by now, it probably won't ever be, except maybe from the possibility of moot and staff failing to meet obligated budget requirements to keep the site afloat.