I think the answer is what I call 'subscribable circles' in this blog post: http://blog.byjoemoon.com/post/12261287667/in-defense-of-the-new-google-reader http:

I think the answer is what I call 'subscribable circles' in this blog post: http://blog.byjoemoon.com/post/12261287667/in-defense-of-the-new-google-reader http://blog.byjoemoon.com/post/12261287667/in-defense-of-the... Which actually works a lot like RSS. You have certain named feeds, e.g. "Unix." Then people looking at your profile can subscribe to that feed if they're interested in what you have to say about Unix.