The Blue Obelisk Group has a single mailing list which you are welcome to join, post messages or questions to, or just search and browse.
For instructions on how to subscribe and how to post messages, see the Blueobelisk-discuss mailing list page.
The mailing list is archived since Nov 2006 at the Mail Archive where it can easily be searched:
You can also browse the mailing list at Gmane or subscribe to an RSS feed of the list: