This document discusses how Twitter uses location data to target advertising. It explains that Twitter has over 284 million monthly active users, with 80% being mobile. It then discusses how Twitter generates user content by encouraging users to share private location data. It also discusses how Twitter monetizes this location data by using it to target ads geographically and based on user attributes and behaviors. Finally, it discusses the technical infrastructure needed to process location data at scale, including issues around data quality, normalization, and geocoding/reverse geocoding.