Live Blogging is a plugin that allows you to insert micro/live blogs into posts with automatic updating of the content.
To see this plugin in use, it's probably easiest to watch this screencast.
Live Blogging is a plugin developed to support blogs that are doing live micro blogging of running events, such as major sport events or tech conferences. (such as the Roses sporting tournament at the University of York).
Using WordPress 3.0's custom post types, the plugin allows you to create these micro blog entries in a stripped down version of the normal post edit screen. These micro blog entries then get included in a post which has been activated as the microblog.
By default, the plugin uses AJAX polling to allow your readers to instantly update what they are viewing, including any new comments posted on the post. For professional bloggers, Meteor is supported, which gives the smoothest updating experience for your viewers and also significantly reduces the load on your server.
Additionally, the plugin also supports integration with Twitter - if activated, the first 139 characters of each live blog entry will be posted to Twitter when they are made.
Using this plugin will give you an advantage over your competitors if you're blogging from live events - your readers will get updates quicker, and it will integrate into your blog better than competing systems, such as CoverItLive.