As a news aggregating and delivery service, Twitter is extremely adept at delivering a news-stream that is localized, topic-specific, and individualized according to each user's needs and interests. The major advantage(and maybe a limitation) is that you, the user, is charged the responsibility of choosing the news sources, i.e. choosing who you will follow.
I primarily use Twitter for following the news. For instance, my feed is localized...I follow local venues, breweries and restaurants in order to stay informed about upcoming concerts or new seasonal brews. My feed is topic-specific... I follow prolific members of the tech-media industry and respected lawyers to keep apprised of the latest technological and legal developments. And, my Twitter feed is individualized...I follow my friends, who both comment and share on both news related and personal topics.
Still, it is global breaking news (the Big Stuff) where Twitter truly excels. When something really big happens, I frequently hear about it first on twitter. It is only after seeing a tweet, that I will then shoot-off to a news site (BBC, HuffPost or ESPN, depending on the topic) for more information than can be gleaned in 140 characters. The only problem, however, is that Twitter has become too good at this, it has become too popular a landing spot for the discussion of these breaking stories. Historically, Twitter has not handled these massive emerging new stories well. Massive, but still relatively 'non-critical' stories such as Apple announcements and Michael Jackson's death have the tendency overload the Twitter servers and 'fail-whale' the site.
My concern is that, if a critical, emergency situation arises (I'm thinking on the level of Hurricane Katrina or 9/11), where Twitter could actually serve to help connect the individuals affected, or provide aid to those who need it, Twitter will not be able to handle it. Apple iPods and Michael Jackson are important stories, but they are not critical situations.
If Twitter is overloaded by the 'non-critical' stories, can it survive a true emergency? Can it handle the Big Stuff? Will its potential, as a social tool for effective and efficient responses to catastrophic or emergency events, be wasted?