Intelligent life like dolphins, neanderthals and mantis shrimp might be not compeltely uncommon. But spacefaring life? It must be incredibly rare. We should have seen some definitive signs of stellar engineering by now. Unless that's what cosmic expansion is, and if so, that's less than reassuring. Tabby's's star was looking like what we were hoping for but doesn't seem likely now.Interesting...
Buuuut... Putting on my tinfoil hat for a moment what if signals like WOW were just carrier waves from travelling ships sending out a "we're ok don't worry" signal back home to let people know they were ok.
I refuse to believe that in the billions and billions of light years of our galaxy that Earth is the single only planet with intelligent life. That's just way too arrogant to think that.