So, back in the original alternatehistory.com thread, one of things I've been doing is having the HIEROPHANT data server respond to queries. Post something like "Query: TERRACE" or "Query: The martian city state considered the most powerful and influential during 4700 AD", and the "server" responds in-character. A fair amount of background material's been revealed this way, though I'm trying to make sure that you don't need to read the server responses to understand and enjoy the story. But, over the next week or so, I'll be posting the more interesting server responses.
If you want to query the server on the blog, post a comment with "Query: XX". Be aware that: first, it can take me a while to actually respond, because I'm busy and almost always have an extensive backlog. Second, the server sometimes responds with "This information is above your security clearance" or the like. And third, the server answers in-character, so it may not always tell the truth.