AlphaGo obviously made mistakes in game 4 under the pressure from LSD's brilliant play. I'd like to know if the "dumb moves" are caused by the lack of pro data or some more fundamental flaws with the algorithm/methodology. AlphaGo was trained on millions of amateur games, but if Google/Deepmind builds a website where people (including prop players) can play with AlphaGo, it would be interesting to see who improves faster.
This seems to be more impressive than the Deep Blue moment. In 1996, Deep Blue didn't make it on the first try. Even in 1997, it has been a draw until the 6th game. Although AlphaGo has 2 games to go, the first three seem to be a clear victory.