Another instructable, but you could add software kind of like the Dr. Eliza program to almost have a natural language interface. This could be an automated help center or even some kind of auto response chat line. You could go one step further and have the tweeting computer issue commands to other computers behind firewalls without having to open a port or human intervention all via a twitter account or accounts.
Note: Twidge is available for the Apple Macintosh and you could probably use almost the same batch files.. Microsoft Windows computers may be able to do the same thing with a program called "tweetc". You definitely you have to use different batch files though. (not a subject of this instructable).
Update: Set up your own twiiter like server: http://www.instructables.com/id/Statusnet-the-Twitter-clone-setup/