1. Mail senders SHOULD NOT generate group syntax.
maybe, maybe not. groups are useful.
They're not used...
they are used, just not terribly often. but the utility of a feature is not
directly related to the frequency of its use.
In practice I've only ever seen groups used in the form To: undisclosed-
recipients:; and at least one MUA from Redmond gets the syntax laughably
wrong, like To: <undisclosed-recipients:;> [sic].
The original idea for groups seems to have been as a way to note the
address book lookup key that was used to retrieve the addresses, but since
that's generally only useful to the sender one can see why it hasn't been
used much. This could be changed with better directory technology
integrated into MUAs, but in the absence of that people have implemented
groups on the server side rather than the client side.
f.a.n.finch <dot(_at_)dotat(_dot_)at> http://dotat.at/
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