scripting.com

WordPress supports PubSubHubBub
  WordPress announced today that they've added support for PubSubHubBub to their product.
  This is great news. More realtime support is a good thing.
  I'm sure some people will use this moment as an opportunity to say bad things about RSS, that's just the way it goes. I've always encouraged people to see more realtime support as a just plain old good thing.
  I would love to see Google support rssCloud in Google Reader and their other products. It would show that they support all ways of doing this stuff.