Computers have mastered Go, a more complex game than Chess!

This is exactly the kind of thinking that leads to articles like the one the OP posted ;).  Practical purposes = meaningless fudging of a hard definition.

I'll give you credit for not saying "for all intensive purposes", though ;).

Even for practical purposes it's not solved - for some correspondence tournaments players are allowed to use engines, and the players who just play the engine choice every move do not win these tournaments

 How do we know the other player is not using engines as well?

People use multiple engines. So I imagine it's fairly straightforward to tell when someone is playing an engine move every time, and when they're not.

richie_and_oprah seems to be trying to revive some past arguments because I don't see how that post deserves such a hostile response. Wrong or not.

In any case, from my own, admittedly modest, go playing experience I would say that strong go players actually calculate quite a lot (only they call it reading instead).

Also, I don't think having less legal moves necessarily makes a game more suitable for brute force approach as long as there are enough options to make exhaustive search impractical. I believe that a bigger difference between chess and go is that it's easier to construct a reasonable evaluation function for the former. In chess important are concepts like material and piece activity which may not be that hard to turn into a code in some approximate way. In go corresponding terms for a human player might be territory, influence and thickness. The first may not be so hard for a computer although not that easy either when territories are unfinished but the latter two concepts (which roughly speaking mean things like loose territorial frameworks and fighting strength) are much more abstract and probably difficult to turn into an algorithmn.

Well alphago just beat Lee Sedol in game one of best of five matches, this is truly a break through in AI.

Amazing to think that human beings can still compete with computers in problems with a limited number of variants where computers have such a huge advantage in calculation.

That's fairly relative though. Computers can preform many operations per second, but many times more are required to solve these games. Neither humans nor computers play by pure calculation... especially in go.

This is much more impressive than the 2 dan guy, wow.

Yup, the pro commentator said that Alphago have really improved from its games against the Euro Champ, which was only about six months ago, it is learning at an incredible speed. When does google plan to build skynet? 2020?

Just being much better than someone else doesn't equate to solving a game. If I come closer to solving a chess study than you does that mean I solved it?