In Holland there's even ISPs that filter porn and stuff, like https://kliksafe.nl . They're used by ultra-religious conservative communities (calvinists). Even adults use it there.

I view this as a much better solution. The people that want it can do their blocking and the rest of us aren't bothered with verifications and stuff.

Personally I belong to the sex-positive movement which thinks diametrically opposite about such matters :)