Hmm, I explicitly considered whether using LLS we should update after each new game and decided it was a mistake, but on reflection you're right. (Of course what's really right is to have an actual prior and do Bayesian updates, which is one reason why I didn't consider at greater length and maybe get the right answer :-).)
Sorry about that.
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.