IMO, when sending to a mailing list, the address of the list should
normally go in "To:". "Cc:" should be reserved for cases where the
is intended for some individual but it is thought the mailing list
be interested to hear about it.
more often than not it's appropriate to Cc a list, since To is often
used for recipients who are expected to act on a message and Cc used
for recipients who just need to be aware of the content of the message.
it's rare that you can expect an entire list to "act on" anything.