Here is a great article on New Scientist that attempts to explain the Fermi Paradox by saying that it is evolutionarily advantageous for a civilization to stay quiet and not broadcast their existence. Seth Shostak comments in the article.
If this is true then SETI first detection will likely be an eavesdrop instead of finding a beacon. Unfortunately from a signal analysis perspective the eavesdrop scenario is far more difficult than finding a beacon.
Make sure you read the full paper here:
What are your thoughts?
It makes sense to fear both contact and eternal isolation.
People's choices on this matter are most probably developed in an irrational way based on statstically unrealible life experience. So I am highly skeptical of arguments to either side. I won't let that stop me!
The most crucial knowledge to inform our decision is how long humans (or replacements that we still care about) will last without intervention. I'm a bit of a pessimist (we won't last long without help) so this pushes me toward more risky behavior (transmissions) in an attempt to save humanity or at least gain a bit of knowledge. Maybe we are alone.
If you're an optimist that thinks human life will continue for millenia given its current course (o_o), then keeping quiet for now may be a better strategy. I don't expect to be around long enough to find out.
How does this affect the search strategy? Well, if the aliens intend us harm, wouldn't they set up beacons to ensnare us? Probably there is enough room in the universe for just about every kind of behavior you can think of, which means some altruists and some nasties will set up beacons.
Given that our radio telescopes are still too small and noisy to detect unintentional transmissions at long distance, we're kind of stuck with searches for proactive transmissions for now. We need a bigger telescope (http://www.skatelescope.org/).
Ironically (if I am using the term correctly) there are probably many many times more folks reading this post than responding to it.
Some may fear controversy, some may not know how to post, some may simply not be interested. Maybe ET has the same issues.
Oh, and I guess some may be way the heck far away from a keyboard.
re-reading the article, I thought of something else.
Given human nature, I doubt that the world will honor a "ban" on transmissions that might be picked up by alien civiliations. There are always disagreeable people who pursue paths "against the flow" of human culture. Everything we create in our culture also creates its own negative side.
So the more we talk about how we shouldn't transmit, the more likely it is someone will. What limits those folks now is the cheap technology to perform transmisssions, and I don't doubt there are already enthusiasts transmitting near 1420 MHz with relatively small dishes/transmitters in their back yard.
If we all agreed that transmitting is bad, there are plenty of alienated people who would like to see the world end, or people who engage in "risky" behavior as a long shot (short cut?) approach to success. As technology improves and comes down in price, these amateurs (or even governments) will improve their transmission equipment. Ultimately, we humans are going to perform the experiment of intentionally transmitting, one way or another.