Real-World, Operationalized Applications of Multi-Arm Bandits Multi-armed bandits are wonderful and have lots of potential applications. However, I don't know many companies or real-world practitioners who have implemented bandit algorithms.

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*What are some examples of multi-bandits that are up and running? By this I mean: An organization (company, government or whatever) has implemented the bandit. And the algorithm is live, performing explore/exploit and touching real-world decisions that change something (large or small). In the real world.

*Refute this claim: "Bandits are an academic novelty. Despite attractive theoretical properties, practitioners have systematically refused to adopt them in practice since their invention in 1952."

Note: I'm not asking for potentially good (new) uses for bandits. There's already a question about that, and I agree there are lots of potential applications. I'm asking what anyone actually has used them to do. Lets list the biggest and most impressive applications!

Multi-armed bandits are commonly used. They were used in Google Analytics and until recently the linked post was a part of the official documentation, but they probably switched to something else in the meantime. Washington Post used them for automated experiments on content placement. Here you can find a presentation by Netflix on how they use them for recommendations. Polish Onet.pl site engineers used it for content recommendations. They are used by Stich Fix fashion e-commerce. Notice that most of those resources are few years old, so not much of a novelty. If you google the phrase, you would easily find many more examples.
