http://www.paulgraham.com/pypar.html
It sure seems Scala's in this "python paradox" land now. My guess is that you need some startups make it big using Go to evangelize it. Google using it is interesting, but I'm not sure it makes it "cool".
Though, I'm not sure Java was ever a language you could use as a skillset filter. Hm.
I don't follow the mailing list anymore, so I don't know if it already led to the same "cargo cult" fanboyship that Plan 9 sometimes evokes, where a lot of the idiosyncratic opinions of its developers (e.g. "shared libraries are bad") are basically never questioned and repeated almost like holy scripture.
I'm not 100% sure would make the argument that "Rob Pike and Ken Thompson made it". Instead, I'd say "it's in use at Google, and all of these other startups..." If 1 or 2 of those startups hit it big (e.g. Twitter or LinkedIn kind of big) that might have a bit more of an "Ooo" factor.
Though I have said, "it's incredibly well thought out, look, Rob Pike and Ken Thompson know what they're doing". I don't sense this quite had the gravitas I was looking for yet. Hm.
Depends a lot on your interpretation of "Cool" though.
I get more of the sense that Google is more "impressive" than "cool".
If I were to use "Google's got it in production" I might be told something like "well they can pull this off" as if they have some unattainable smarts or something.
Whereas a "cool" thing is more about just simply taking a risk.
Come to think of it, that's kind of a funny definition. Oh well.