Mozilla Messaging launched in February 2008. From their mission statement:
We subscribe to the Mozilla Manifesto. Furthermore, we believe that email is the killer app of the Internet, a vital tool in modern society, and one which has not evolved as much or as fast as it should have. We’re driven to improve the experience of people communicating with each other on the Internet.
Our first tool in this endeavor is the Mozilla Thunderbird email client, which is already in use by millions of people worldwide. Using a collaborative, participatory process, we will work to make Thunderbird the most useful, enjoyable communications tool possible. It’s a huge challenge, but we believe that by finding like-minded people who want to help, we can have a real impact, and have a lot of fun doing it.
In order to provide as many opportunities for participation as possible, we strive to be open and transparent in our operations.”