This seems like a good place to get into my theory of why aliens don't contact us.
The Kardashev scale [http://en.wikipedia.org/wiki/Kardashev_scale] describes different types of civilizations that might potentially exist on other planets. Michio Kaku also explains it in this video.
Here's what I think. In order to achieve Level 1 status, a civilization must first achieve global consciousness. This implies that every Level 1, 2, or 3 civilization in existence has done the same. Once a civilization reaches that point, they are welcomed into the galactic government with open arms. Before achieving the technology, a civilization must overcome certain cultural hurdles. Its citizens must put their greed aside, and work together for the greater good of the team. The definition of a Level 1 civilization implies that they learned to stop destroying their planet, and instead work with it. My guess is that the vast majority of civilizations do not survive the transition to Level 1.
As Michio Kaku explained, there is likely a Level 3 civilization waiting for us to achieve Level 1 status. So why not help us? Why not destroy us?
Helping us could potentially prove disastrous to the galactic community. All Level 1 civilizations have the culture to be able to handle the technology. They are at a point where they would be useful to other civilizations, and could work together peacefully, for mutual benefit. Any civilizations that would cause problems never made it in the first place.
The reasons to not destroy us should be fairly self evident at this point. For one, they don't need our resources. They have that well under control. They have nothing to fear from us, because if we might pose a threat, we will just destroy ourselves. Above all, in the event that we are able to achieve Level 1 status, we could end up being helpful to other civilizations.
