The Mozilla Foundation has been supporting Thunderbird since its inception, delivering some promising results. However, in a posting to her blog, CEO Mitchell Baker said that Mozilla's first priority is, and will continue to be, its open-source browser, Firefox.

According to Baker, Mozilla's Thunderbird effort "is dwarfed" by the energy it spends on the Firefox browser and the ecosystem around it:

As a result, Mozilla doesn't focus on Thunderbird as much as we do browsing and Firefox and we don't expect this to change in the foreseeable future. We are convinced that our current focus - delivering the web, mostly through browsing and related services - is the correct priority. At the same time, the Thunderbird team is extremely dedicated and competent, and we all want to see them do as much as possible with Thunderbird.
The Mozilla executive offered three options for a new Thunderbird structure which include creating a new non-profit entity just for Thunderbird, creating a Thunderbird subsidiary within Mozilla, or releasing Thunderbird into a community project like SeaMonkey.

Baker noted that Mozilla doesn't have the best answer yet, and don't expect to make any decisions without a broad public discussion and involvement.