matt jones | work & thoughts | Constant, partial, sorry what were you saying? is a characteristically pertinent comment by Matt Jones on the relationship between the problem of "absent presence" (a symptom of our always on, information overloaded condition) and designing for meaning:
"I think it's fantastic that journalists, bloggers, technologists and hackers are starting to pay more attention to sociologists, ethnographers and other theorists on the human condition and technology's effects. However, research and analysis takes you only so far - synthesis means design. It would be a shame if designers couldn't benefit from this recent, reinvigorated dialogue, as I think the other parties would definitely benefit by including them."
Matt's point, if I understand it correctly, is that rather than responding to the issue of absent presence by simply turning off inputs (e.g. rationing email weblog reading time), user experience designers should also seek to ensure that we can easily, intuitively focus on what we need/want to focus on: "Great design creates meaning from information".

Howard Rheingold is - I think - touching on a similar issue in Does Mobile Telephony Disconnect People from City Life? http://www.thefeature.com/article?articleid=100296. He's suggesting places are changing because people's ears, eyes and thumbs are elsewhere aided by their mobile devices.
What seems to be left out of the equation of people, place, device, media is deeper understand of just how people differ. Personality type and communication preference play a big part in how/whether people, phone, meet, write etc... and how 'there' they are when there.