I would argue that the laws on child pornography are not effective at this time. The reason for this is that it is so easy to make and disseminate child pornography on the internet that it is very hard to catch and prosecute everyone who does so. This is particularly true because of the international nature of the child pornography business. It is too easy for child pornography to be made in foreign countries and then accessed by Americans. In this way, technology (in the form of the internet) has made it very difficult to catch child pornographers and the laws on the books are, therefore, ineffective.
The so called "effectiveness" is only as good as the money in the budget to enforce the laws with the manpower needed.
Many departments today are short on thier "authorized strength".
We most often hear when a speeder is caught they say to the cops, "don't you have more important criminals to catch".
Too much crime, not enough cop to citizen ratio.