I remember arguing about this in law school, over a decade ago:
A federal law intended to restrict children’s access to Internet pornography died quietly Wednesday at the Supreme Court, more than 10 years after Congress overwhelmingly approved it.
The Child Online Protection Act would have barred Web sites from making harmful content available to minors over the Internet. The law had been embroiled in challenges to its constitutionality since it passed in 1998 and never took effect.
COPA was a patently ridiculous law, the product of populist grandstanding more than anything else. It put the onus on me, as publisher of this site, to make sure your little precious was unable to see something that you didn’t want her to see.  The law was challenged virtually the moment it was signed, and it’s amazing that it took 10 years to finally be done with it.  I do fear that now that it’s off the table, some enterprising congressman or senator is going to take up the cause of government content regulation (probably some young and ambitious Republican congressman plus Lieberman).