#2 Oct 22, 2006 19:41
See Comment::send_email_notifications() in /blogs/inc/MODEL/comments/_comment.class.php.
From looking at the code it should use the address of registered users as the From address, but not if it's a visitor (who has also given an e-mail address).
IMHO it's a bad thing that the email address of members gets used: a spammer would "just" have to subscribe to comments and then gets real email addresses.. :/
I'll file a todo request to change this and use the built in message form instead (linking there from the email body).
But on the other hand you are right and it would be handy to have the mails ready for replying. It should be an option somewhere, defaulting to not use the email addresses for public mails.