Little over two years ago, a couple of San Diego teenagers earned high school diplomas after taking every class since kindergarten via computers through an online charter school.

Their stories were considered a novelty at the time. Since then, the concept of computers as classrooms has moved closer to the mainstream.

More and more students have turned to computers for a chance to quickly re-take failed courses needed to graduate high school, while others enroll in classes for the first time — including Advanced Placement courses not offered on their campuses.