The document provides an introduction to Apache Unomi, an open source context server. It discusses how Unomi can aggregate user information from multiple sources to provide a unified view of the user context. This allows for personalized experiences and targeted content while also giving users privacy controls. Unomi provides functionality like user profiling, segmentation, event tracking, and integrates with other systems through its REST API and plugin architecture. It uses Elasticsearch for storage and is designed to be highly scalable and extensible.