As it happens, one of the mods, /u/agentdcf, wrote a paper about the beginnings of the sub - You can read it here.

I'm also trying to find a post that's an interview by the Reddit admins of our subreddit's founder, /u/artrw, not long after the sub was created. The hunt continues...

edit: well.. I've searched and can't find what I'm looking for, but here's one by /u/artrw from 2012, telling about the early days - [meta] The culture of r/askhistorians