I can give you a little history of the OpenACS piece of it. OpenACS was originally known as ACS/pg, that is, ACS for PostgreSQL. It was started by Ben Adida and Don Baccus in late 1999 (not sure of exact month; my e-mail archive of the acspg-devel list starts in December, but I know it was in the works prior to that). Roberto Mello, Jamie Ross, and I also were there at the beginning; Roberto did lots of testing and doc work, and there were others involved, too. I did the initial AOLserver 3 port of the postgres driver (I had just started maintaining the PostgreSQL RPMs that summer) and fixed some issues that Ben really appreciated. Don further improved the driver. I ported what are now known as the FOR_ACS_USE extensions from the Oracle driver used by ACS in early 2000. Lessee, the biggies were ns_table and ns_column, which AOLserver 3 had dropped from the nsdb API.
Red Hat has the archive of the old ArsDigita forums. You can find one of the initial threads at http://rhea.redhat.com/bboard-archive/webdb/0005oj.html (some of the names should look mighty familiar!). The whole archive is available, and will give you a good idea of the history from early 1999 through late 2001/early 2002. See http://rhea.redhat.com/bboard-archive/ for Red Hat's home page for the archives.
Ok, I found the initial message thread. OpenACS, 'nee ACS/pg, started in the thread http://rhea.redhat.com/bboard-archive/webdb/0006Fr.html when Ben and Don began collaborating. This was December 1, 1999.
Also search the forum archives here; I found https://openacs.org/forums/message-view?message%5fid=26737 and https://openacs.org/forums/message-view?message%5fid=14474 (this last one shows the name change to OpenACS).
I found an old bboard post from August 2000 in my ACS/pg e-mail archives, but am not sure which bboard it came from, or I'd post a link. This message discusses a visit by someone related to OpenACS to ArsDigita and a meeting there, where ArsDigita finally realized the open source potential. I can forward it by e-mail (it's probably too lengthy to post here).
Wow, lots have changed since those days. Joel's release manager work, the coming and going of Peter Marklund, wow. Lots of things have happened, and I am glad I have been a small part of it.
