1) With the first statement when I say "we should suspect intelligent civilizations to developed very quickly on galactic scales" I should have clarified that I meant on the scales of deep time. If a civilization like ours - that is currently experiencing a dramatic increase (over the past few centuries) in technological evolution existed for another 1 million years - I contend that we would be very loud. If you were in the Milky Way you would know about us either directly or indirectly. But your point is well taken.

2) I like your second idea. I suppose that one could best be incorporated into my first point "we are the first." It could also be that we are currently developing on the same galactic time frame. I think it would be really improbable but I guess with 100 billion earth-like planets it is completely possible. Very cool idea.

3) Well I did state in the article that I don't think it is probable that intelligent civilizations are ignoring us. I think this is one of the least likely scenarios. However, under the framework I imagine this scenario - I am talking about a type II-IV civilization ignoring us, so I think they would probably know of our existence even with a tiny radio bubble. Any civilization like this would have circumvented the speed of light barrier (if it can be) and would have a fairly good idea of what was going on in the galaxy. That is why I don't think one exists at the moment (unless they are ignoring us - which I don't think they are).

Thanks for your responses. I think the way you think!