Selfies are popular among both genders. Sociologist Ben Agger describes the trend of selfies as "the male gaze gone viral", and sociologist and women's studies professor Gail Dines links it to the rise of "porn culture" and the idea that sexual attractiveness is the only way in which a woman can make herself visible.[31] Writer Andrew Keen has pointed out that while selfies are often intended to give the photographer control over how their image is presented, posting images publicly or sharing them with others who do so may have the opposite effect—dramatically so in the case of revenge porn, where ex-lovers post sexually explicit photographs or nude selfies to exact revenge or humiliate their former lovers.[31] Nonetheless, some feminists view selfies as a subversive form of self-expression that narrates one's own view of desirability. In this sense, selfies can be empowering and offer a way of actively asserting agency.[32] Copyright law may be effective in forcing the removal of private selfies from public that were forwarded to another person.[33]