Summary: Web and online communication and interaction is asynchronous. As such the delay, be it a matter of seconds or several days, disintegrates the sense of "being there" and "shared time" that characterizes co-presence, simultaneous, and spontaneous interaction. People have the time to consider themselves consciously, to tell rather than talk, and some of this comes out in online and social media as cold, distant, and self-oriented rather than other-oriented. And yet a great deal of talk now happens in a mediated fashion. The implications for the design of social software, online interaction, online community, and social media are significant. And they will become very interesting as these media become more synchronous.
Just as it is difficult to convey our availability (or unavailability) to others through technology, it can be difficult to bring conversation to a close. In face to face exchanges, we can look at each other while wrapping up; that allows us to reach a kind of emotional closure simultaneous with the ending of the conversation. But through the screen, be it in email, texting, IM, chat or otherwise, we simply disappear. The consequences are often more confusing for others than for us. Where'd they go (Did they really go? Are they lurking?), should we feel slighted? Am I projecting or did she just duck out of that chat? You can imagine where this would go if we applied it to online dating!