[ExactoKnight]

> And perhaps a warning about shouting at the Universe. Although it's probably too late to fret too much about that.

Any civilization sufficiently advanced to threaten us already has the capability to see we exist. For those with a large enough telescope, we have been emitting signs of life to the rest of the galaxy for billions of years.

It's only more recently that we have been showing signs of intelligent life (through radio waves and changes to our environment). These signs have not yet propagated throughout much of the galaxy yet, and there is a good argument we ought to get as advanced as possible as quickly as possible, so we can defend ourselves before others become aware of our intelligent existence.