Neutrinos might be a better medium for intergalactic communication, since they can travel through most objects.
replyOr we can all just think big thoughts at the same time... https://en.wikipedia.org/wiki/Calling_Occupants_of_Interplan...
There isn't anything in the way that would require this. I mean, we can see back to (shortly after) the Big Bang.
replyKind of contrived, but if you're sending a signal from some other planet to our planet, depending on the geometry, there will be times of the year that our local star is in the way of photons.
replyAlso, if you're sending out photons from a planet, chances are there's a local star nearby. Stars tend to be a broad-spectrum photon source, which is going to make it tough for receivers to decode the intentional signal.