Agreed on all points.
LW was one handshake away from DeepMind, we interviewed Shane Legg and referred to his work many times. But I guess we didn't have the right attitude, maybe still don't. Now is probably a good time to "halt, melt and catch fire" as Eliezer puts it.
I'm confused what you would have done with the benefit of hindsight (beyond having folks like Jaan Tallin and Elon Musk who were concerned with AI safety become investors in DeepMind, which was in fact done).
There have been a couple of brief discussions of this in the Open Thread, but it seems likely to generate more so here's a place for it.
The original paper in Nature about AlphaGo.
Google Asia Pacific blog, where results will be posted. DeepMind's YouTube channel, where the games are being live-streamed.
Discussion on Hacker News after AlphaGo's win of the first game.