Meaning and purpose of the Subject field

[Random832]

Cameron Simpson <cs at zip.com.au> writes:
> Besides, changing the Subject line is _supposed_ to break the
> threading in these contexts: such clients clearly consider the
> discussion topic (subject) as sufficient definition of a thread, and
> changing the topic should imply a new thread to such simplistic
> clients.

This makes sense for the change from "old" to "new (was: old)",
which nobody was advocating against (after all, there's semantic
content - they wouldn't have changed the subject line if they
didn't consider it a new discussion topic), but I think there is
a reasonable argument that changing it a second time from
"new (was: old)" to "new" is frivolous.