Embracing, building upon and contributing to Open Source products has become a key instrument for businesses to focus research and development efforts on differentiating, consumer-relevant innovations. Collaboration with Open Source communities requires a cultural and procedural fit based on the governance norms applied by the communities. Businesses, but also standard setting and government organisations depend on understanding these norms to successfully cooperate with Open Source communities. Based on a study performed at TU Berlin, the presentation discusses common community governance norms that collaborators should adhere to when using and contributing to Open Source products.