Twitter traffic is reaching such huge volume it is becoming statistically accurate and contains so much real-time data that it is becoming relevant. Like a survey, the larger the sample the more accurate the conclusions, so if 500 Twitterer's are giving real time information about a large-scale event the cumulative data can prove very precise.
This new source of data and it's accurary have not gone unnoticed by California authorities who used it to track the recent brush fires in real time. They found the Twitter data more reliable and more timely than aerial tracking in plotting the direction and progress of the hundreds of fires.
The new mass sensing data producted by thousands of individuals reporting their live situations has been compared to an ant colony's ability to chemically relay information. Might have homeland security ramifications, especially when GPS locators are factored in. Spooky and interesting at the same time.