While I have been participating in S@H for almost 10 years now, and will continue to participate for as long as I am able, I have recently begun to believe that we may have a futile task on our hands. I no longer believe that ETI would still be using the electromagnetic spectrum for their communications; it's too slow and limited.
Consider that everyone believes that if there are other civilizations out there, they will be more advanced than we are. We are just getting started with the implications of quantum mechanics, so it makes sense to believe that they may already have a good grasp of it, and possibly already use it in their everyday lives. Take the possibilities of quantum entanglement, where two atoms are made to be identical to each other, both change when one changes no matter how far apart they are. This could be used to create a super-secure communications device, if sufficient atoms are "entangled" in the two consoles. Near-instant (as far as we now know) nearly uneavesdroppable communications between two parties. Even once (if) we reach their technological level and understanding of quantum mechanics, we still would not be able to listen in on their communications.
I believe the only ETI we're currently able to detect are those ETIs who are at our level or slightly behind us.