X.Org's Mailing Lists
xorg-announce is for announcements about Xorg releases and releases of related Xorg components. It is not a place for discussion.
xorg is for general purpose discussions and support questions.
xorg-devel is for development discussions. Patch review and development discussion can go there.
xorg-driver-ati is for discussions on ati driver related issues.
x-packagers: Discussions among people who are interested in packaging X binaries (mostly distro maintainers)
xorg-test is the general discussion list of the XTEST Project.
Xcb is the general developers discussion list of the Xcb Project.
Nouveau discusses the NVIDIA reverse engineering project Nouveau.
Logging Lists (not for posting)
The xorg-commit mailing list archives commits to the xorg repository.
The xorg-test-commit mailing list archives commits to the XTEST Project repository.
The xorg-team mailing list is where bugzilla sends notices about bugs filed against the xorg tree.
Other X related developers lists not directly part of the X.Org Foundation.
The xdg freedesktop standards and specifications mailing list.
The XKB-Config project hosts a mailing list for discussion of XKB keyboard layouts and usage.
The xorg-europe mailing list is to announce and discuss events and meetings in Europe.
Mailing List Archives (Unofficial)
archive.netbsd.se, browse, search, RSS-feeds.
Deprecated Lists Archives
The archives of deprecated X.Org mailing lists can be found here.