[saulrh]

Two things.

First, when something is always available and you are always aware of it and taking data from it, it becomes part of you in the same way that your eyes or your clothing are part of you. It's part of you when you're talking to people in the same way that your computer is part of you when you're having an email conversation. It's entirely possible that you with google glass is generally less socially adept or more distracted than you without google glass, but I don't think the effect will be as extreme as you fear.

Second, and more important, is that Glass doesn't force you to break eye contact or change your body language. Having worked for years with people that wear head-mounted displays religiously (look up a guy named Thad Starner), I can tell you that those two features actually make a huge difference. Instead of imagining a person using a cell phone in the middle of a conversation, imagine a family talking around the latest episode of Star Trek or across the dinner table - you aren't really looking at other people, but the conversation feels perfectly natural anyway.