>> Classifying messages by arbitrary rules is a function of filters
>
> Folters must have an action. "Mark it with label green" is such an action.
So it "give it Low priority". Your point?
>> As I understand it, Labels allow you to say "All mail from X becomes
>> labelled Y (and goes green)" instead of what can currently be done,
>> which is "All mail from X becomes priority Y (and goes red)". I am
>> trying to have the advantage of one over the other explained.
>
>
> In the latter case, I am changing a property of the message as the
> sender sent it, right? What, if I want to still see the Priority as the
> sender sent it?
As mpt says, the Priority it arrives with is what the sender thinks its
priority should be to you. If that isn't your priority, then you change it.
> What about the average user, who doesn't like "senders being able to
> make messages red in their INBOX" (using the priority), and who don't
> know how to use filters to undo it?
How does the labels feature solve this problem? By removing the colour
hint from the Priority? Yes, the problem goes away if you break the
feature. So? :-)
Gerv