Sure, you can send a mass e-mail or a group text to your friends and family. But with Twitter, there's no awkward wrangling of names or addresses. Instead, everyone who subscribes to your account sees your update; if your profile is public, everyone in the world can see your Tweets. Just as with an e-mail, they can chime in with a response, which is also public.
The overall effect is similar to an old-school message forum, with threaded conversations that are easy to follow. Unlike those forums of yesteryear, these conversations take place in real time. More than that, the conciseness of Tweets makes them more conversational. You share your ideas with brief phrases instead of wordy replies.
Twitter is useful for more than organizing a roller-skating outing. Its speed and simplicity are well-suited for disseminating breaking news or sharing details on real-time events. Whether a tornado is bearing down on a small town or a high-speed police chase is happening in a major city, users often Tweet about it. The result is a nearly instantaneous hive mind of sorts, in which we don't have to wait for evening TV news to stay up-to-date on world events. Now they unfold in real time, on Twitter.
Twitter has also played at least some role in areas of political unrest. From Iran and Egypt to the United States, digitally savvy protesters deploy Twitter as a tool of high-speed communication, either to organize followers or to update them on critical events.
When U.S. military operatives killed Osama bin Laden on May 1, 2011, Twitter exploded with the news prior to any sort of television announcement. The avalanche of Tweets began when Sohaib Athar, a computer programmer in Abbottabad, Pakistan, Tweeted about helicopters and chaos near bin Laden's compound, in essence providing a distant play-by-play of the raid. With that news, Twitter blasted up to more than 5,000 Tweets per second. That record withstood other major events like the Super Bowl and Britain's royal wedding.