I work for a software development firm which produces interactive 3D solutions for the web.
Thoughts about SETI and SETI@home
I am fond of a quote from Jack Cohen, noted biologist - "Given reasonably complex chemistry, life is downhill." It seems clear to me that natural selection for self-replicating systems means that life is virtually inevitable given sufficiently friendly conditions. I think that we are likely to find evidence of simple life on Mars, and on Jupiter's moons. Complex life will be much rarer, and tecnologically advanced life rarer still. The benefits of finding even simple lifeforms will be a more profound insight into our own origins.
Given the vast distances between the stars, I feel that the benefits of contact between us and other technologically advanced lifeforms will surely outweigh any potential downside. If the closest contact we have is information exchange, we have little to fear, but much to gain.
Humans should be transmitting on exactly the bands we think are most likely - the ones we are listening in on. Otherwise, we have a potentially farcical situation akin to everyone calling a party line and sitting there with their hands over the mouthpiece of the phone saying "Shh! I'm trying to determine if anyone else is here." Without people actively transmitting, we're relying on leakage into the bands of interest, and we are very radio quiet in those bands.
I run Seti@Home because it has a better than 0 chance of success!