It's perfectly understandable that human memory limits arise here, I was expecting such a response. Are they some minutes of this meetings? No blame if that's not the case, Wikimedia DE for what I found already release a large set of archives, including the IRC logs of the open meeting organized each weeks. Simply if there is no trace of this, it's really unfortunate that considerations for such a crucial decision fell in oblivion while so many log are available for far less important points in term of governance.My reference was to in-place discussions at WMDE, not the open meetings with Markus. Each week we had an open demo where Markus usually attended. As I remember the May-discussion, it was just a discussion in the office, there was a reference to an earlier meeting. It is although easy to mix up old memories, so what happen first and what happen next should not be taken to be facts. If Markus also says the same it is although a reasonable chance we have got it right.
Just as a side note if it wasn't clear, by community, I was talking about the Wikimedia community at large. And if I don't make the precision, you can assume that it's how it is supposed to be denoted in my sentences.As to the questions about archives on open discussions with the community. This was in April-May 2012. There was no community, there were only concerned individuals.
Thank you for all this sourced informations.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, while first post on the subject page is from 30. October. The stuff from before October comes from a copy-paste from Meta. 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 a free license, allowing the reuse of the data in many different scenarios.", 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. I'm not quite sure when it was changed to CC0 in the footer, but it seems to have happen before 31 October 2012, at 19:09. First post on Q1 is from 29. October 2012, this is one of several items updated this evening.
It is quite enlightening to start at oldid=1  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.