My tip on the latest episode of This Week in Google is how to enable real-time updates of your site’s feed to FriendFeed (right now), and more services like Google Reader as they release support for PubSubHubbub in the future. If you missed the instructions on the podcast, here they are in bookmarkable text. It’s very simple for blogs which use Feedburner for their feeds.
In Feedburner, click on the feed name you want to PSHB-enable. From the Publicize tab, click on PingShot in the left hand column of available services. Click on “activate” (see screenshot). Once this is done and your feed refreshes, you can view its source and see
rel="hub" href="http://pubsubhubbub.appspot.com" attributes. This means that when you publish a new post, Feedburner will let the hub know, which will in turn notify subscribers in real-time. Here are these same instructions from the horse’s mouth. If Feedburner’s not your thing, there’s also a WordPress plug-in which will do this for you.