I guess there are two factors which determine whether a person asks him/herself "is this REAL?" - the lack of visual/auditory cues as in e-mail and text-only chat environments, and the fantasy-driven quality of the online relationship, as in some multimedia chat environments. Maybe this just boils down to one factor: how REAL does the other person look, sound, and behave on your computer (i.e., how well does the CMC imitate a face-to-face encounter). I believe that whether or not a person thinks "This is real," they STILL are always expressing some real aspect of themselves. Even in a fantasy, you can only be what you are.