a Header epidemic?

[Jean-Pierre A. Radley]

filePro Mailing List propounded (on Thu, Oct 02, 2014 at 03:33:11PM +0000):

| Great word!  I, too, only got the "moon" part
| ... etc ...
| -- Mark Kaminsky

Note who my MUA decided was doing the propounding when I hit 'R' to
reply:: not Mark Kaminsky, but this list itself.

Is there an epidemic? I ask because of the From: Header in Mark's
message:

From: Mark Kaminsky via Filepro-list <filepro-list at lists.celestial.com>, Mark Kaminsky <mbkaminsky at yahoo.com>

What's with this "via" business in the From: Header???  Last week it
seemed to have to do with mail flowing through aol.com, but Mark is
posting through yahoo.com.

-- 
JP