Indeed, what would we tell them? I guess since I'm a pretty simple layperson, I was sort of taken aback by Dr. Hawking's comment that if we were to make contact with a more advanced civilization, it might not go too well for us ("Hey... he's right... we do sort of tend to crush ants and impose our will whenever necessary - and it's usually found to be necessary!").

I think a fascinating field of study would be the preparations for this dialog and potential meeting with an alien species. What do we say - and not say? What do we ask? How do we project ourselves? And how have our communications been received - what information have we given them that they've actually understood? And if the roles are reversed, what kind of messages are we expecting to receive, and what are we not prepared to receive?

Do we invite them to dinner, or wait for an invitation ourselves?