"But, if you’re forwarding an email or get involved in a thread later, your email client usually does not include full email addresses in the quoted reply/forward content.

"Thus, you see 'Jim Smith' was looped in early on but don’t have his email address to loop him back in. Or you are forwarded a message that needs follow up but all it says down below is 'From: Mark Johnson (Acme Co).' What now, Mark?"

Attaboy, Devin.