I think the problem is that if you open it up to more than one bit, it
begs the question of what the actual number of bits such a button is.
ARF has a bunch of options added at the request of ESPs intended to
support multiple buttons, e.g., spam, opt-out from this list, opt-out
from everything, etc.
As far as I can tell, the only ones that have ever been used are spam
and virus, the latter done mechanically when the message has the bit
pattern of an executable.
Most people have only the dimmest understanding of opt-in, opt-out,
what they subscribed to, etc. There are a lot of obvious analogies to
paper mail and such that are totally misleading, but close enough to
confuse people. One button is plenty.
I also think that most of the useful info from multiple buttons could
be extracted mechanically from the mail stream, e.g., if the sender has
sent multiple messages before and it has a List-Unsubscribe: header,
it's probably an opt-out, not a spam complaint.
R's,
John
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