This document discusses how Windows Azure supports open source technologies in several ways:
1) It provides native support for open source development runtimes like Node.js and Python.
2) Developers can build Windows Azure solutions using open source tools like Eclipse.
3) Windows Azure includes open source services like HDInsight, which provides Hadoop, HDFS, HBase and other big data technologies.
4) Mobile apps can be developed for Windows Azure using open source technologies like Android.
The document argues that Platform as a Service models like Windows Azure help drive adoption of open source by managing the infrastructure and allowing developers to focus on their code.