There is a reason behind this How To Do post and the reason is the news that I will share with you. As of January 16, 2014, this site is on it’s own domain! It now holds the ubuntusense.com name. I brought the domain from WordPress, well did it with them, and I gained five e-mail addresses to use for forwarding to my personal e-mail account. I’m using one (firstname.lastname@example.org) as my everything that is Ubuntu related e-mail address, inducing mailing lists. What allowed me to do this is the fact that you can set a secondary e-mail with Yahoo!. I believe that you can do this also with the other major e-mail services. So, I made that @ubuntusense.com e-mail address my primary and that allowed me to send with this e-mail with Thunderbird. You can do this via “Settings” for your e-mail on Thunderbird and you change the “Default Identity” e-mail address to the e-mail address you want and you can also add a new address and use that as a secondary e-mail address.
How To Do: Get An E-Mail Service to Send with Another Address on Thunderbird