Twitter communications in mass emergency: contributions to situational awareness.

The popular microblogging service Twitter hosts 160 million users who send almost one million 140-character messages (known as tweets) per day. In times of mass emergency, many use Twitter to gather and disperse information. With so many tweets sent at any given time, locating and organizing timely, useful information during these safety-critical situations is a task best suited for automatic methods. However, training machines to correctly identify and subsequently extract tweets that contribute to situational awareness an overall picture of what is going on is a multi-faceted task that involves understanding what types of information people tweet during mass emergencies, how information differs depending on the type of situation, how various types of information are linguistically constructed, and how we can represent this knowledge in a computationally tractable way.