@astraleureka @GossiTheDog maybe I'm giving too much benefit of the doubt but keeping an RRD of the usage of the "someone is typing" notification service in Teams would be totally normal, expected and provide the described data. Obviously they also know how many active meetings or messages in general are going on at any time as well.

Maybe the takeaway is that _any_ centralized service becomes exposed to incalculable amounts of incidental data and needs retention policies to keep risk low