The METI (Messaging Extraterrestrial Intelligence) is the attempts to transmit messages to search for extraterrestrial civilizations.
METI has generally been thought to be risky (e.g., "the fear of annihilation by an advanced civilization may not be limited to Earth, and it may help explain the silence of the cosmos.").
Various methods (especially safe ones) of doing METI are of interest.
Treat galaxies like CD drives to send directional laser updates of our civilization, and survive in the minds of the distant future civilizations.