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What you're describing is a particular mailing list configuration (one often seen today); not what mailing lists are . Traditional mailing lists (such as ones created by a vanilla install of GNU Mailman) do not work they way you describe. They work like this: 1. You send a message to a mailing list address. This address belongs to a software agent which sends the message to everyone. Your From: header is clearly pres…
What you describe certainly used to be common, but it's not anymore. You didn't say why the old style is better. I find it frustrating for a mailing list because invariably a long thread is going to have missing messages. In the context of a mailing list the default behavior should be to reply to the list and setting the Reply-To takes care of that nicely. Btw, the "because I've been doing it for n years" argument ge…
Reply-To: stomps over the option of replying privately. It can still be done, with manual steps. Worse, someone might not be paying attention, and just use Reply out of habit, thinking it's a private reply, when in fact it is being broadcast to the list. It's very sneaky!
The old style is better because it is more convenient and non-broken. It keeps conversations intact by letting people have a debate with the mailing list without subscribing to it, and doesn't rudely re-program your Reply button into doing Reply All.