[alkonaut]

I use pseudonymization in the sense of having persistent identifiers for users/machines/etc that cannot be reversed on the server side.

Basically: just like the usernames on hn are pseudonyms it’s important they are persistent so you can follow who wrote what despite not being able to attribute posts to physical persons. That is: hn is a pseudonymous forum rather than anonymous.

The hash(localSalt + PII) is provably not PII. But it’s still making the data possible to correlate. The telemetry event I send on Monday can be attributed to the same source as the event I send on Tuesday.