@Mage Re: Yes very significant.
> Is any of it a milestone for real AI? NO.
On the contrary, in the case of Go this is a milestone for 'real' AI. Of course there is some very specialist programming going on but the point of this particular event is that the AI is not just 'searching a database for solutions', it is taking it's knowledge, gleaned from what it has already infered from that database, and applying it to a novel situation, one that isn't in its database. It is not computing the best solution from a known set of solutions.
Regarding your example of crows and babies: so a crow can figure things out but doesn't have intelligence? a baby will develop a level of intelligence over time but has none at birth? At what point do you say something has intelligence? When it is as smart as you? Nearly as smart as you? Smarter than you? 4 years of age for a human? 6 years? Adulthood? You can certainly say that the AI that was tasked with winning at Go is smarter at Go than either the crow or the baby, or indeed the best humans.
You are, of course, referring to a general AI rather than the narrow AIs that are acheiving things in the real world and this is not here yet but the Go victory is another significant step on the road from narrow to general AIs. So, yes, it is a milestone for 'real' (general) AI.
I'm not saying when we'll get there or even if we will but I think the odds are in favour of it happening at some point. The thing is, we may not even recognise it when we do.
(PS - crows & babies: I thought it was Dabbsy who was doing the obscure Human League references? http://www.theregister.co.uk/2016/02/12/send_tortuous_standup_ninethirty_meetings_back_to_the_dark_ages/)