This talk presents OW2's efforts, experience, vision and methodology to assess the market readiness of open source software. If ''open source software has won'' it remains that many conventional managers are not comfortable with it : rating open source market readiness can be a powerful tool to help decision makers. This presentation will cover: - the value chain of open source software; - the OW2 Open-source Sofware Capability Assessment Radar (OSCAR) platform; - the first version of OW2 OSS Market Readiness Level (MRL, derived from NASA's TRL or Technology Readiness Levels).