You're invited to join the xproc-dev mailing list, a public discussion forum for implementors and users of XProc: An XML Pipeline Language.
The W3C set this up for us a while ago, but I don't think I ever remembered to announce it. If you're a user or an implementor interested in XProc, please join the xproc-dev mailing list.
If it's about XProc, it's fair game on this list.
Comments:
Just to add that you can subscribe by sending a message with the subject 'subscribe' to xproc-dev-request@w3.org.
Details, details. (Thanks, Jeni! :-)
More details: list archives at http://lists.w3.org/Archives/Public/xproc-dev/