Unprecedented advances in Internet technologies with multimedia capabilities have enabled pornography and adult content to be widely and freely distributed as easy as a click of a mouse through various means such as YouTube, Facebook, and Tags.Protecting children from unnecessary exposure to adult content has, therefore, become a serious problem in the real world. In particular, the considerable perversion in pornography and the exposure of children and the society to such perversions leads to moral decay.Constructing an appropriate¯lter for pornographic images is a major concern in modern society;however, this area poses challenges.This study aims to shed light on a content-based technique that employs an anti-pornography machine and to encourage researchers to study this adult image¯ltering technique. In this study, we discuss models of skin detection and their advantages and disadvantages in real life. We also elaborate on the pornographic image classi¯er using a feature extraction process and its classi¯cation process, along with the possible di±culties it may present. This study also analyzes anti-pornography techniques based on skin detection and discusses their strengths and weaknesses.