Social media and big data can have important practical applications in public health, disaster management, transportation, and urban planning. Data scientists are using machine learning algorithms, computer vision, and natural language processing to collect and analyze social media data (such as Facebook and YouTube) and environmental sensor/camera data to study human communications and movements. These big data technologies can be powerful tools to predict short-term future events, such as flu outbreaks, severe air pollution, traffic congestion, the weather, and patterns of disaster evacuation. At the same time, these technologies monitor users’ digital footprints, opinions and geolocations. Ming-Hsiang Tsou, PhD discusses the challenges in social media analytics, including data noise and biases, fake news, and data privacy.