Analysing and understanding the European Data Economy has recently become a key con-cern for policy makers willing to enable data based services and products in Europe and will-ing to exploit all opportunities deriving from new (Big) Data technologies. Although the Eu-ropean Data economy is still “emerging”, it is of utmost importance to identify and remove, at this stage, the barriers for its further development in order to achieve a well-functioning and competitive Digital Single Market. This study is a first attempt to characterise the legal, technical and other types of barriers which currently prevent the full deployment of the Eu-ropean Data Economy and which limit Business to Business (B2B) data sharing and re-use in Europe. Based on this analysis, a number of policy options for the future are put forward and considered from a coherence, effectiveness and efficiency perspective. This assessment shows that, at this stage of market development, policy makers should adopt horizontal non-legislative measures in order to build a better ground for a flourishing European Data Economy. The aim of the study’s first part (Task 1) is to gain an understanding of whether and, if so, how online platforms' T&Cs negatively affect existing and potential professional users. To this end, the study analyses the T&Cs and community guidelines used by a wide set of online platforms. It covers 102 platforms, with a broad and appropriately balanced mix of platforms, including both large and small players, and a balanced geographical coverage. Given that a number of the large platforms (for example Amazon, Facebook, Ebay, Expedia, Salesforce, Uber, Rakuten, Zalando, Groupon, Spotify, ASOS) have been included in the review, a significant part of the overall B2B platform business within the EU is considered within this study.