[svlug] OT: header for showing messages on emails in Outlook

[David Rosenstrauch]

Anybody recall:

Back when I used to use Outlook (maybe 2 yrs. ago) I used to see emails 
from Linux/FOSS people sometimes come across that had a special header 
included which would cause Outlook to pick up the contents of the header 
and display it in a special yellow "alert"-like box over the email. 
FOSS people used to (ab)use this header to include goof alerts about 
things like dumping Outlook for a real MUA, etc.

Anyone know what I'm talking about and/or what the relevant header was? 
   Google's not helping me here.

TIA,

DR