It appears to me that anonymity frees the individual from the social and cultural pressures to conform. For the "new" surfer, there are no barriers... Nobody says "no" that has any meaningful affect on the individual. There are no body language signals that say, "don't say that", "I don't want to hear that," "that's an awful thing to say," Infact, a response can almost be construed as positive feedback.
We all have certain internal instinctive triggers that drive us to want some basic things for survival, food, water, shelter, sex. Cyber space only affects the last element. In the real world, sex can be divided into other sub-elements, including acceptance within a social group. But in cyberspace, that need is mainly non-existant, for the new surfer anyway. Consequently, anonymity allows some voyarism, expression, and searching allowing the individual to act out their instincts without negative feedback.