Originally Posted by KyleGoetz
It is reported that "boku" is used often by young women nowadays. Natives have said as much on here, too. The Internet is rife with the same observation, and I heard it some, too, when I lived there. Although the type of girls I hung around with at university tended to be slightly girly.
Though it's true that it is used by some young women, it doesn't occur at the frequency that this comment may suggest. The oldest girl that I have personally heard use it has been a HS senior. Preteens would use it the most (though just a small percentage of them) and as they grow, they just "learn and accept" the cold fact that it isn't socially 100% accepted and start using other first-person pronouns.
In my personal observation, girls attending single-sex schools use it more often and for more years, and they also seem to feel it easier to use in all-female situations. You will simply not see college seniors addressing themselves as ボク at job interviews.