In my opinion, if our ever-expanding Universe is virtually endless then so are the possibilities. We cannot be arrogant enough to believe that we are the only form of intelligent life; random or otherwise. Even if the Universe is finite, it's current mass and our own existence lend credibility to the potential for extra-terrestrial life. It is undeniable.

I believe our thirst for knowledge fuels many an endeavour. As for transmitting a signal or beacon for others to follow, well we should just be careful, for what we wish may not be what's best for humanity. Maybe concepts of good and evil are our own, and such things as ethics and virtue may or may not be 'universal' concepts. I guess basically we'll have to deal with contact when it is made, and made public. I just hope our world is in a better place at that time.

I run SETI for the possibility.