I've come to believe a person's "tenure" online (how long they've been online, how many various types of interaction they've experienced) influences how "real" we perceive online interactions to be. With time, we all experience or hear of horror stories (e.g., man posing as woman in chat rooms on AOL and later attempting to blackmail married chat partners). Personally, I've become more cautious regarding online exchanges--less likely to unquestioningly accept what others "say."
Another aspect affecting "reality" or "trust" in online communications involves shared commonalities--or lack of them. Years ago the online community comprised a lower percentage of the general population--a high percentage of "geeks" and academicians. The population of the net is becoming increasingly representative of the population at large. There's increasing diversity in educational experience, interests, values, and perceptions it seems to me. These differences contribute to misunderstanding and resultant flaming--with a frequency, quickness, and severity I can't imagine happening in the real world. It seems to me this quickness and severity of flaming indicate a lack of appreciation that others are, indeed, "real."
I wonder if the online world represents primarily entertainment for some. WebTV can now bring alt.anything into the comfort of your living room...how far we've progressed from "Pong"! (Or have we?)