Ralph,

Use "Message Ignore Thread".

Thats the "you don't want to read this" marker I mentioned (I've set the
"watch or hide" column to be visible - I "watch" my own messages, causing
replies to them to stand out).

You can hide ignored threads so they are not visible at all

Although I was aware that I could create message rules, I was not aware I
could change views in a similar way. So thank you for both mentioning it
as well as the thorough explanation. :-)

Regards,
Rudy Wieser