The development ICT provides many benefits in business, shopping, leisure, finance, information exchange, and community life with a variety of people. However, due to anonymity, a characteristic of cyber space which one can hide him yourself, there are many negative effects such as cyber crimes, use of illegal contents, malicious messages, game addiction, etc. In order to resolve such problems, causes behind cyber crimes need to be determined according to users' personal and psychological attributes. This study dealt with the causal relationship between online community users' degree of anonymity perception and posting malicious messages. Especially, the study was focused on reviewing existing studies regarding anonymity and looking into the effect of anonymity which has been divided into the types of social, visual, definitive, and location anonymity on posting malicious messages. Based on the study results, this study make a contribution in establishing a standard for controlling the degree of anonymity in laying out online community service designs that could reduce the amount of malicious messages in online communities and the phenomenon of cyber verbal violence.