One of the immutable laws of technology is that anything technology creates technology can undo. It can easily be circumvented. It is the antithesis of what libraries have always stood for and fought for, and of the core political ideal of the Internet - that information wants to be free. And there is virtually no evidence of real risks to children that would warrant such a drastic step as the building of sophisticated censorship technology. In addition, this technology is demeaning and offensive.
Kids hate it.
Ask them yourselves. Those young enough to need it should be supervised by human beings. Older kids should not be censored in this way. In Santa Clara County, California, for example, librarians have addressed the so-called pornography problem by holding a series of workshops to help families learn to navigate the Internet effectively and safely. Libraries could instruct children in what to do when confronted with unexpected or unwelcome imagery.