It forces communication, intimate, meaningful communication that is normally derailed by the temptation of physical intimacy in real life. When you consider how a net relationship can last years, something must be given its due.
It teaches the lost art of human intrigue and mystery, seduction and temptation as a constant, rather than a means. True, only your minds touch, but an incredible journey lies there.
Is it cheating? It is the DEFINITION of cheating -- telling more truth, sharing more of yourself, to and with someone you shouldnt be.
You last me on that last "shouldn't." Why shouldn't??