Governments are one of the largest producers and collectors of data in many different domains and one major aim of open government data initiatives is the release of social and commercial value. Hence, we here explore existing processes of value creation on government data. We identify the dimensions that impact, or are impacted by value creation, and distinguish between the different value creating roles and participating stakeholders. We propose the use of Linked Data as an approach to enhance the value creation process, and provide a Value Creation Assessment Framework to analyse the resulting impact. We also implement the assessment framework to evaluate two government data portals.