Japanese Android content company Ai Point has a popular smartphone service dedicated to female comics as well as a adult content site called Keitai Dougakan.
Android site Keitai Dougakan brings offers and array of adult comics and videos via smartphone to its members—a third of which are females. It's not only male-male boys love comics that are popular with females, but hardcore pornography that feature either "handsome" or gay performers. That site also has adult game apps for download as well as fan-made erotic manga.
According to a Keitai Dougakan spokesperson, many female customers are reluctant to purchase or rent adult material in a retail setting, but are more comfortable consuming it via smartphone. It's an increasingly popular way to view adult films.
Last year, when former Metal Gear fan girl Minako Komukai made her dirty movie debut, her flick was released simultaneously on disc and digital formats, such as Keitai Dougakan.
While pornography is widely available online for free, there appears to be a sizeable female audience in Japan willing to pay for it. This is probably related to a longstanding view in Japan that you need to pony up cash for things and not download them illegally. Or it could be that these female viewers feel more comfortable viewing adult content on a smartphone—a far more intimate device—than Googling on a computer.