Technically, any Yahoo Group with publically viewable content should be subscribable as an RSS feed, using the following format:
... but things appear to be broken. This kinda sucks, given that LJ allows you to read RSS feeds nowadays.
Then again, there are a lot of things about the way that LJ handles RSS feeds that kinda suck right now too. People should have control over their RSS feeds and be able to do more than just syndicate largely useless headlines. Until this is done, there won't be any true interconnect between LiveJournal Server based sites... which is really bad and evil from an open-source standpoint.
My other big pet peeve about how LJ handles RSS feeds is that it treats them too much like regular friends. For example, I subscribed to a handful of feeds and put them in a customized friends list for my RSS feeds, but since these feeds are on my friends list, anyone clicking on it (myself included) now gets bombarded with a ton of RSS feeds. Not good... especially if and when people start adding more feeds to their friends list. I will probably want to subscribe to over 30 feeds in the near future, but that pretty much means throwing away the usability of my existing friends list for anyone who actually wants to see what my friends are. Likewise, I suspect this could effect the "friend of a friend" feature negatively, as well.
What really needs to happen with friends lists is some kind of customization, where I can define everyone on my friends list that I want to see... or that I want you to see, which might be an altogether different list.
This raises a bunch of privacy issues. if someone meets someone else on LJ and starts to develop romatic/sexual ties that they want to be able to write about indirectly, but ideally not make public knowledge, then it would be nice to give them a bit more control to do that. Hang around LJ enough and you will discover details of all sorts of liasons that weren't initially intended to be public, but were easily deduced by comparing notes between the person who posted and the people in their friend's list.
So, I guess what I'm saying is that I'd like more interconnectedness *and* more privacy. I know that might sound contradictory, but it's not... trust me.