I only recently saw this word used in a magazine article; it couldn't be more accurate I think. Except for those who make their living with a camera - wedding and portrait photogs and journalists - this is probably what the rest of us are doing... trying to figure something out, trying to tell others about us - our surroundings, family, travels, desires, expressing our emotions with photos. The artist in us influences the image, hopefully making my photograph different from everyine else's.
I believe that every photo we take/make is a form of a self-portrait, but actually turning the camera on ourselves is a unique experience. I think for some, it is a method of assuring a one-of-a-kind image. ;)
"Because self-portraits permit direct nonverbal self-confrontation, they can be not only validating and empowering, but also the most threatening and risky kinds of photos to open one's emotions to -- which is precisely the reason they are such quick and effective activators of deep process work in therapy situations." Phototherapy Site