Fine Structure

A slightly different take on the Fermi Paradox from Karl Schroeder (retold by Kevin Kelly): we assume that all these advanced civilizations would bleed the same amount and type of electromagnetic radiation that we currently do. But being sufficiently advanced and having finite resources, who's to say their efficiency hasn't advanced to the point of infinitesimal loss due to inefficiency? This would push the civilization back to the point of being not as obviously identifiable as we are at many light years distance.

Considering the age of our civilization and our current rate of change, it doesn't seem all that unlikely that we could be out of phase with a particular communication method or power source available to a civilization with a ten, a hundred or a thousand millennia head start on us. Good food for thought.