Not many players that registered right around the AlphaGo paper and the LSD vs. AG games have stuck around, but the number of users registering per day has definitely increased.
Clearly, the site got a bump with the AGvLSD match.
Go is hard. People were probably not expecting the learning curve. Can you see the win loss rate of people in the aggregate registered since the dawn of the super human computer era versus the same time last year?
I know the wind nearly as many people registering this time last year. Normalize it however you do that.