Paul Barham from Microsoft wrote an article about how Visual Studio Online Supports True Cross-Platform Development. As I had mentioned in a previous blog post, this has been a nice new trend coming from Microsoft as they expand cross-platform capabilities, enhancing the usage of VSO for big enterprise with heterogeneous environments. Notice the list of available service hooks:
The article does a brief summary of the many ways that VSO enables cross-platform development, from using git as the source control format, and thus supporting, for instance, XCode, to allowing different build systems such as Jenkins to enable Continuous Integration to getting it all tied together and traceable using a Team web backlog.