Google Analytics supports multi-armed bandits

It's a kinda odd implementation. To quote:

Once per day, we take a fresh look at your experiment to see how each of the variations has performed, and we adjust the fraction of traffic that each variation will receive going forward.

So not exactly a fresh look... I imagine this limitation is due to Google Analytics' infrastructure. They still don't have good real-time support, so I expect they're running their bandit algorithm on their batch infrastructure. Still, good to see the biggest player moving forward.

<obplug>If you real real-time banditry, my startup http://mynaweb.com/ does this</obplug>