Can we at least partly unify the communications, so that you could follow Carolingia via email or Facebook and participate in the same conversations?


Sure you can. vBulletin (or some similar package) would handle the thing nicely. You put together a news website, with the various relevant people allowed to publish news items. Those items appear on the site's front page, as well as being tweeted and sent to Facebook. You then have threaded discussion forums behind that news site (and a thread for each published news item by default). All nice and searchable for folks who are interested in digging through for old information.

One could subscribe to various forums or threads to watch for new items coming in (so, say your Guild has a thread for announcements - anyone subscribed gets an e-mail about a new post in that thread, just like they were on an e-mail list, but you don't have to be on the list to find that thread if you aren't in the guild)

News items, discussions, and archives of all of it all in once place.