"Mozilla has been supporting Thunderbird as a product since the
beginning of the Foundation. The result is a good, solid product
that provides an open alternative for desktop mail. However, the
Thunderbird effort is dwarfed by the enormous energy and community
focused on the web, Firefox 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.
"We have concluded that we should find a new, separate
organizational setting for Thunderbird; one that allows the
Thunderbird community to determine its own destiny..."