The 21st century has brought a data rich age, with online technologies intersecting with and impacting upon nearly every area of human life. Combined with a growing range of methodologies now available, opportunities abound for using big data within positive psychology research and application. What can big data reveal? Will big data replace self-report measures, allowing cost-effective, real-time, ecologically valid tracking of wellbeing across entire populations? Can big data be used to personalize and improve interventions? Can machine learning techniques be applied to others types of data? Using linguistic data as an example, this talk will illustrate probable applications of big data and machine learning within positive psychology research, based on current capabilities, what may be possible in the near future as computer science and positive psychology intersect, and problematic aspects that emphasize the need for research with and applications of big data to proceed cautiously.