You could opt to start with introducing broad strokes via out-of-game medium (like the blog) and leave all the specifics to in-game. For example, maybe giving a rundown of the factions and what they represent. Or, possibly, a narrative similar to what Joe gives you if you start asking him, pertaining to the history and stuff that happened before you came along. Just somethin' to hook folks and get them interested.

Another option a lot of games seem to take is introducing the developers person by person and having them write about or show off a bit of what they do. I'm personally a sucker for those, but then I like games and companies that have a more 'personal' feel like that. It also seems to help when trying to gain 'indie cred', heh.