The Wall Street Journal's self-title "The Numbers Guy", aka Carl Bialik, tries to track down the root of an often quoted statistic that 100,000 websites contain images of child sexual abuse. He discovers the number is largely an urban legend. While child sexual abuse is indeed a serious matter, the more approprieate statistic would be an accurate assessment of the number of those involved in such criminal activity. It's possible that a few criminals are reponsible for the majority of the crimes (in producing the material). The more efficient means of policing this would be to find these people, just like busing the Columbia drug cartel some years ago.
Users of such material represent an easy target, by pedophiles will never be cured and will always be there. Thus, the governments of the world should cooperate to find the producers (just like they have been).