Your observation about geeks fearing phone conversations is spot on, but I think it has to do with more than just turn-taking.  I think it's a general social anxiety that manifests more strongly with phone calls because they're easier to avoid or procrastinate and because they often intrude social anxiety into a very safe, non-challenging social environment.  I would guess that face-to-face conversations that are easy to avoid or postpone are just as anxiety-provoking as phone calls.<p>Anyhow, I am certainly a phone-phobic geek.  When I was a young child, I was terrified of talking on the phone.  I was too geeky to understand the social aspects of a phone call, but I was smart enough to know I didn't understand most of what happened during a phone conversation.  When my parents called somebody to ask a question or invite them somewhere, it would take fifteen minutes.  Typically, I had one goal in mind, such as asking my friend Jon if he wanted to play.  That was all I understood, but I also understood a phone conversation was supposed to be more complicated than that, and that I had to be polite to whoever answered the phone.  I had terrible performance anxiety.<p>Strangely, I still have an aversion to making phone calls to people I don't know well.  Even simple, low-risk, impersonal tasks like calling to ask a restaurant's hours or calling the dentist to make an appointment produce a significant amount of anxiety.  The more often I talk to someone on the phone, the more the anxiety decreases, though.  Talking on the phone to my family and close friends generates no anxiety.