You are surely asking you what does this stand for. Well this is my campaign against all those who send HTML mail. Whenever I see someone using that format (it's easy, my email program doesn't support them) I send him the following email:
Subject: Please, stop sending HTML mail
Body: Greetings.
I've seen you send HTML emails, something that is not bad at all, but I would like to give you some reasons to stop sending emails in that format:
We live in a free world, and I cannot order you to do something, therefore I ask you a favor: please stop sending HTML emails. If you have problems desactivating this feature, come here: http://gradha.sdf-eu.org/anti_html_mail/intro.en.html
Considerate also the following:
Thank you.
And obviously, if you reached this far after recieving my email, you surely want to know how to desactiate the feature. You don't need a big computer knowledge to do this, however, the programs usually hide their options. For that reason, select below the mail program you have and I will try to help you create a better world for our children :-)