From Fedora Project Wiki

Netiquette Guidelines

In this page, I'm going to post some of guidelines related to Email Netiquette based on RFC 1855.

Reply at the bottom

If you are sending a reply to a message or a posting be sure you
summarize the original at the top of the message, or include just
enough text of the original to give a context.  This will make
sure readers understand when they start to read your response.
Since NetNews, especially, is proliferated by distributing the
postings from one host to another, it is possible to see a
response to a message before seeing the original.  Giving context
helps everyone.  But do not include the entire original!

Watch out reply-to address

Be careful when you reply to messages or postings.  Frequently
replies are sent back to the address which originated the post -
which in many cases is the address of a list or group!  You may
accidentally send a personal response to a great many people,
embarrassing all involved.  It's best to type in the address
instead of relying on "reply."