[Lancaster] Help needed with email formating

[Ken Hough]

I'm sure that some of you "professional" IT people will be able to help me 
with a problem that a couple of my friends have wrt with their email 
clients/or email systems.

Email clients that I have used always inserted ">" to mark all lines of text 
from included previous messages. This was/is done by default. No problem!

Without these additions, message threads can become very confusing to read.

The email clients/systems of two of my friends do not insert ">" characters. 
These guys are both Microsoft users, but this doesn't appear to be 'normal' 
Microsoft behavior.

Where in email clients/systems does this insertion normally occur and how can 
this be enabled/disabled?

Ken Hough
Kendal
Cumbria
UK