* Running commentary on an event.
* Random thoughts.
* Announcements (news sites, software updates, blogs, etc.)
* Sharing interesting links
* Conversations
* Fiction told one line at a time.
* Tips of the Day
I’m sure if you think about it instead of dismiss it you can come up with other uses.
All of it tied into a single feed that can be access via the web, via a multitude of desktop applications, via smartphone apps, or even via SMS on mobile phones, making it ubiquitous.
Sure, many of these things can be done via email, or RSS, or instant messaging, but Twitter — or rather, a system like it — provides a simple way to combine them all into one easily-accessed stream.