I am writing my own blog (every one should, it's good experience). I have implemented Atom and RSS feeds, and they are used by a number of readers. Most of those readers are using Google Reader, who at the moment polls my site regularly for updates.
I would like to setup a publish Subscribe (PubSubHubbub) option as documented here, and I would like to serve as my own hub, that is integrated the hub protocol into the app as opposed to having a separate thing to maintain or relying on a third party.
My questions are:
Sounds good to integrate your CMS with your own Hub. That's the way a lot of people will/should do it!
Right now, FriendFeed and livedoor Reader are the two main subscribers who consume PubSubHubbub. Other services (like favit.com) also have support. Other services have support in the works, including Google Reader.
You need to implement a Hub. Definitely look at Web Glue, which is written in Ruby (perhaps you could help him extend the codebase). You should be able to integrate it into your existing system.
Good luck! Let us know how it goes on the mailing list.