OK, I have to confess that this idea spawned after I realized that I have only seen half-dozen people using e-readers in public so far and they are all female.

I suppose you could argue that women read more than man (more books in public transport anyway) and thus dedicated devices like e-readers would more likely appear in this public's hands.

Also, even the most compact of the e-readers is still unpocketable so unless you want to carry it around in the open you will need a handbag for it.