Highlighting Dave Winer's comment on the issue of federating rss.chat servers,
Yes, use OPML, create a list of servers. That's what software that wants to work with federations will require as input.
I'm leading RSC in the same direction, "connected instances" will have a export to OPML, so that other instance can import the same connected instance if they wish, users already have OPML import/export so that's done already
but then I want to go further with OPML, right now if you import an OPML into RSC, the "folders" within the OPML, how each RSS is categorized gets flatened, RSC just import the RSS feeds themselves, but very soon I want to allow the users to import OPML subscriptions and then display the feeds in the same way they are organized within the OPML, possibily adding filters in the UI to display/hide specific collections, so depending on the mood, hide politics, or hide sports etc..and only see on the screen what the user selected (politics, climate, sports, tech etc..)
the idea would be to make the reading experience tunable among other things, I'm also tempted to have a Explore tab, where users could subscribe to existing RSS feeds, effectively enabling shared pools/delivery for RSS items, without having multiple subscriptions/polling for the same feed for each user...not sure I'm being very clear here but I think there are quite a few stuff that we could improve in that area