Twitter is an extremely multi-dimensional tool. The London Underground tube system has started using it so you can track if there's delays and on what lines, etc.
I have a sync between my WordPress blog and my Twitter as well so that when I post a new blog it updates my Twitter with the blog title and link.
I also heard of a park ranger in Africa using Twitter to track the animals and the goings on in the park. That guy has thousands of followers now.