From the article: Earthquake Shakes Twitter Users: Real-time Event Detection by Social Sensors, WWW ’10: Proceedings of the 19th International Conference on World Wide Web, 2010, by Takeshi Sakaki, Makoto Okazaki, and Yutaka Matsuo:
Twitter, a popular microblogging service, has received much attention recently. An important characteristic of Twitter is its real-time nature. For example, when an earthquake occurs, people make many Twitter posts (tweets) related to the earthquake, which enables detection of earthquake occurrence promptly, simply by observing the tweets. As described in this paper, we investigate the real-time interaction of events such as earthquakes in Twitter and propose an algorithm to monitor tweets and to detect a target event.