Semantic data management refers to a range of techniques for the manipulation and usage of data based on its meaning. Semantically enabled linked and open data have been published at an increasing pace in recent years, and this technology has been adopted by major industrial players, including Google, Yahoo, Oracle, Talis and IBM. But to reach their full potential of becoming a transformative technology enabling a data-driven economy, there are important research challenges related to semantic data, particularly regarding maturity, dynamicity and the ability to process efficiently huge amounts of interconnected semantic data. SemData brings together some of the internationally leading research centres in the area of managing semantic data to address these challenges.