My HN username (Rygian) is PII because it can be used to identify me indirectly (HN has a log of my username connecting from IP x.y.z.w, and my IP address is PII).
In the US there is precedent (existing court rulings) against IP address being PII. Obviously, IP address is not very good PII, and never guaranteed to be able to identify someone.
Whether HN has a log of it is an assumption I don’t have a way to verify. Lots of privacy-conscious sites purge connection logs often and/or refuse to keep them for this very reason.
