My guess is they are making it up. AWS has no public information, but there are some high profile customers that have migrated https://aws.amazon.com/elasticache/customers/.

Without sources, it's a "statistically worthless" comment :)

My guess is most people are using Redis via cloud providers. Did any cloud providers switch away from Redis?

AWS supports Valkey for Elasticache, and they actually bill it 33% cheaper. We use it and it works well.

AWS Elasticache gave a nice discount to switch to valkey w/ 1 button click no downtime migration path

ValKey is cheaper in AWS than Reddis

Wasn’t the whole point (or one of the major ones) of Valkey so that AWS could use it?

Based on Internet-accessible services the number of Valkey servers is low (~120):

https://trends.shodan.io/search?query=valkey_version+port%3A...

Here's a chart of all Redis-compatible services (~55,000):

https://trends.shodan.io/search?query=port%3A6379+redis_vers...

And how representative are publicly accessible redis/valkey instances for redis/valkey usage in general? And can shodan even differentiate Redis from a Valkey instance setup in a backwards-compatible way without being able to authenticate?

In absolute numbers probably not highly representative but the relative numbers are meaningful to measure adoption. And no, it requires the user to disable authentication in order to get the service details to differentiate between Redis and Valkey. But again, you can compare unauthenticated Redis to unauthenticated Valkey to see how the percentages are changing over time.