[AKSF_Ackermann]

Content-addressed email breaks mailing lists, as those need to be able to add headers for subscribe/unsubscribe/list id, etc. There is a reason DKIM allows you to pick which headers to sign.

[kamma4434]

Do we need mailing lists at all?

[ninalanyon]

I Linus Torvalds needs them. And that's a good enough reason for their existence as far as I'm concerned.