One thing that immediately came to mind upon seeing the title is the way that efficient (digital) radio communications look much more similar to noise (due to i

One thing that immediately came to mind upon seeing the title is the way that efficient (digital) radio communications look much more similar to noise (due to information density) than old analog communication methods. The article seems to be looking at things from an energy-usage perspective. Why don't we detect Dyson spheres and other large-scale technological projects? Maybe the most efficient ways of harnessing the energy of a planet blend in with the natural processes of the planet itself. Or, as a sibling comment suggested, maybe the civilization that makes (alien) people happiest is one that outwardly resembles the world they evolved in.