Comment by thegrim22

The vast majority of (radio) SETI relies on primarily searching for intentional, powerful, repeating, beacons/signals. We have scores of unexplained, suspicious looking signals that we just discard because the signals never repeated and so we'll never know what they were and can't ever make any conclusion about them. The only really unambiguous signal we can detect is a powerful repeating beacon, and so that's all we really look for. Also, any "random" non-beacon leakage another civilization might internally produce is expected to be too low-powered for us to pick up hundreds or thousands of light-years away. Nobody in their right mind would design their internal communications to be so insanely inefficient that they'd be blasting it strongly, unambiguously, potentially omnidirectionally, for us hundreds/thousands of light years away to detect. What an insane waste of energy that would be.