Twitter is brain dead
Have they not heard of clustering? If they ran several instances of their app over several clusters then it would be extremely difficult for it to go offline. Surely their popularity has bought fresh investment to do something about their poor reliability image.
Personally I don't see why any relatively busy person would use Twitter. It's a waste of time unless you happen to have a lot of spare time to suffocate under everyone else's trivial tweets which are often as brain numbing as watching Big Brother or as pretentious as a woman's gossip magazine. However, I'm sure there are perfectly good examples of how Twitter can be used as a legitimate tool to enhance an existing application or process. Answers on a postcard...