I think, and hope, that extraterrestrial life exists. Statistically, it appears highly improbable that we should be the only sentient species in this vast universe, let alone the only life form, considering the long and varied history of life on our planet.
We are making good progress toward a complete radio survey of the sky. Even if the results of the past surveys showed nothing of interest, we must keep trying. And even if radio-astronomy doesn't yield results, it's only a beginning, we must also examine others spectra : optical, neutrino, etc.
The possible benefits of such a discovery are too great to estimate. And the only indication that another intelligent race exists elsewhere in the cosmos should decuple our space efforts to truly build a spacefaring civilization.
Should humans transmit a beacon for others to find? That is already too late to stop so! Our civilization has been transmitting radio and TV signals since the dawn of the age of broadcasting. Extraterrestrial civilizations could examine at their leisure our developpment through our news coverages, our movies, our obsession with gameshows, and other good and not-so-good stories detailing our collective lives. And I hope they will be kind ;-)
SETI@home is a marvelous project, that permits everybody to participate in a grand experiment. I am honored and proud to be in such company, to work with millions toward this great goal. The distributed nature of SETI@home is, to my mind, a call to scientists around the world to share their work with the lay public and a new paradign to conduct research such as meteo modeling or folding molecules. | 
