This document discusses continuous integration (CI) services, focusing on Visual Studio Online (VSO) as a CI service. It provides an overview of key aspects of VSO for CI, including using Git or GitHub as code repositories, running builds across various platforms and languages through agent pools, and integrating with tools like Jenkins. The document promotes VSO as a fully-hosted CI service for developing applications on Windows, Mac, Linux, and with languages like .NET, Java, Android, iOS, and more.