Sociability's value comes from privacy
boingboing.net
boingboing.net
Of course, the original post is only one paragraph longer than the boingboing excerpt.
I regard these expectations as very self-centered. It really only takes a small short conversation and most people realize that it's self-centered to expect immediate responses to text/IM.
If someone needs my immediate attention I don't have a problem with them phoning me, or finding me in person. If they expect immediate attention from text/email/facebook then they are choosing to use the wrong communication medium.