readwriteweb
All blogs on the WordPress.com platform and any WordPress.org blogs that opt-in will now make instant updates available to any RSS readers subscribed to a new feature called RSSCloud. There is curretnly only one RSS aggregator that supports RSSCloud, Dave Winer's brand new reader River2. That will probably change very soon (Read More)
The difference is, instead of the typical feed reader that checks for updates every few hours, this one checks for updates in real time. In other words, every few seconds.