A great article on the actual gulf that separates machine learning from a human toddler. Transfer learning is the biggest part of general intelligence. The ability to intuitively map together information about the world. So while AI is very good at an increasing number of specific tasks, it can't adapt prior learning on a previous task to a new one in a way that rapidly increases competency. It must learn from scratch every single time.
http://www.newyorker.com/tech/elemen...ce-video-games
This may or may not matter. As PZ Myers (an AI skeptic) has said before, the attempt to create a general AI intelligence that models closely after humans is an impossible dream. Human consciousness is too contingent on way too complex a set of variables, and is also set in physical circumstances that would never exist for an AI. Every emotional change you have is accompanied by your brain bathing itself in a cocktail of hormones.
Now machine learning may or may not be reaching a point where its decisions exceed human reasoning. Certainly, that appears to be the edge that Alpha Go had over Lee Sedol and it is what lead Deep Blue to triumph over Kasperov back in 1995.
Chess has not diminished since then, and neither will Go. Human-machine learning enhances the capacities of both. Human-machine tandems in chess are more effective than individual machines or humans.
This is a milestone, yes. But we just don't know whether it is merely technical or cohesively cultural, yet.