0) First, would it be a good idea to announce your world's existence? Robotic explorers who might exist in your neighborhood might decide your world is worth harvesting or colonizing.
1) If yes, then wouldn't sending a high-power announcement signal need to be obviously unnatural, i.e., containing very little data? Short trains of pulses with pauses that count up in binary perhaps?
1.1) "Visible light" seems like an anthropocentric assumption because there's not necessarily a reason other entities couldn't sense microwaves, IR, UV or even possibly fissile radiation. Furthermore, cybernetic "evolution" seems like there would be many possibilities for different senses. Maybe there is something particular efficient about the visible spectrum, such as polarized laser light remaining distinguishable extreme distances?
2) If said entity wanted to send a little more data as well, wouldn't they use a slightly different carrier or modulation but it wouldn't necessarily reach as far? Or, send it, as mentioned, more slowly?
