(Instructions for the Bad Religion Mailing List)
First, log in to your Yahoo account as usual. You will see a very familiar menu of functions like these:
Select the link called Options. A screen with ten or so categories of options appears. The one you want is Mail Preferences:
You should set both options for screen width, that is, the width of the box in which you read and create messages. Pick a number between 65 and 72 (at the very most).
The next thing you want to set is how Yahoo formats your text in replying. As the illustration below shows, select "Forward as inline text" and "Quote full message." (Remember to trim away any parts you are not replying to. That's a must! If you don't select "Quote full message," an entire BRML digest will not be available in your reply.)
Save your changes and leave the Options screen.
When actually typing a reply to the BRML (or a new message from scratch), make very sure indeed that the Plain Text button is selected. It's just below the message-composition box.