The community started to emerge in August with the
first attempts to go public. On Wikidata_talk:Introduction there
are some posts from 15. August 2012,[1] while first post on the
subject page is from 30. October. The stuff from before October
comes from a copy-paste from Meta.[3] Note that Denny writes
"The data in Wikidata is published under a free license,
allowing the reuse of the data in many different scenarios." but
Whittylama changes this to "
The data in Wikidata is published under [http://creativecommons.org/publicdomain/zero/1.0/ a free license], allowing the reuse of the data in many different scenarios.",[4]
and at that point there were a community on an open site and had
been for a week. When Whittylama did his post it was the 4504th
post on the site, so it was hardly the first! The license was
initially a CC-SA.[8] I'm not quite sure when it was changed to
CC0 in the footer,[9] but it seems to have happen before 31
October 2012, at 19:09. First post on Q1 is from 29. October
2012,[5] this is one of several items updated this evening.
It is quite enlightening to start at oldid=1 [6] and
stepping forward. You will find that our present incarnation
went live 25. October 2012. So much for the "birthday". To ask
for archived community discussions before 25th October does
not make sense, there were no site, and the only people
involved were mostly devs posting at Meta. Note for example
that the page Wikidata:Introduction is from Meta.[7]