If you want to provide live coverage of an event but 140 characters are too few, live blogging is the only way to go.
Live blogging, in essence, is just a series of updates and mostly just a label and a warning that the event is still unfolding and that the post may not be the most accurate or the most spell checked.
There's nothing really complicated about it, just edit a post you already published with the updated information.
For example, users can post updates from the front-end, i.e. the actual blog page rather than going to the dashboard. What's more, the posts are automatically refreshed when new info arrives, readers don't have to keep hitting F5.
Unfortunately, the add-on is only available for WordPress VIP users, i.e. blogs like TechCrunch and GigaOm, not your average, everyday blogger.