I wrote up a blog post a couple years ago about how to integrate PubSubHubbub yourself.

http://blog.newsblur.com/post/20371256202/building-real-time...

That blog post includes what to look for in the RSS feed and how to subscribe to updates. It's written in Python, but that's just a short-hand way of saying it's in plain english.

It also includes details on how to then push the real-time updates out to clients using JavaScript and Socket.io.