Thanks for the fish. n/t
When the puzzled recipient replied "n/t?" I realized the usage wasn't as common as I'd thought.
Apparently the placement of "n/t," to denote no next in the body of the email, dates back to the days of Usenet. (I found the reference at UserFriendly.Org.)
Also worth checkout is NetLingo, The Internet Dictionary, which talks about an email/chat adjunct I'd love to try out, called a Zaplet. Ever used one?